bluuebunny/crossref_metadata_2025 huggingface dataset:
Graft subsidence after instrument-assisted anterior cervical fusion
Authors: Tye Gary W. , Graham R. Scott , Broaddus William C. , Young Harold F.
Published: May 2009

Object. Bone grafts used in anterior cervical fusion (ACF) may subside postoperatively. The authors reviewed a recent series in which instrument-assisted ACF was performed to determine the degree of subsidence with respect to fusion length, use of segmental screws, and patient smoking status, age, and sex.

Methods. Charts and implant records were reviewed for all 70 patients who underwent instrument-assisted ACF during a 2-year period. The procedures, grafting materials, plate types/lengths, and patient smoking status were recorded. The immediate postoperative and follow-up lateral radiographs were analyzed. The plate lengths and lengths of the fused segments were measured in a standardized fashion.

The mean intraoperative and follow-up fusion segment lengths were 54.3 and 51.9 mm, respectively. Greater subsidence occurred in multilevel fusions than in single-level fusions. There were noticeable changes in the position of plates or screws on 14 of 70 follow-up x-ray films. No new neurological deficits related to graft subsidence occurred, and the reoperation rate was 3%. There was no statistical relation between subsidence and the following variables: segmental fixation, smoking status, sex, age, or dowel size when corrected for length of the plate. Hardware migration correlated significantly with plate length in cases of two- and three-level fusions.

Conclusions. The length of a fusion segment decreases in the immediate weeks following instrument-assisted ACF. Construct length is the most important determinant of subsidence. When designing multilevel cervical constructs, consideration of the effects of graft subsidence may help to avoid hardware-related complications.
Bilateral decompression of lumbar spinal stenosis involving a unilateral approach with microscope and tubular retractor system
Authors: Palmer Sylvain , Turner Robert , Palmer Rosemary
Published: May 2009

Object. The authors studied a consecutive series of patients with spinal stenosis in whom surgery was performed by a single surgeon who used a microscopic tubular retractor system (METRx-MD); patients underwent prospective evaluation involving radiography and magnetic resonance (MR) imaging.

The objective was to assess the feasibility and surgery-related efficacy of performing unilateral-approach bilateral decompression and utilization of METRx-MD instrumentation in patients with spinal stenosis.

Methods. Seventeen consecutive patients with spinal stenosis underwent bilateral decompression; surgery was performed via a unilateral approach using METRx-MD instrumentation. The procedures were performed on an outpatient basis after induction of general anesthesia. Preoperative and 3-month follow-up plain radiographs with flexion—extension views were obtained. Preoperative and postoperative MR imaging was also performed. All studies were assessed by a single radiologist blinded to the clinical results.

Twenty-two levels were surgically decompressed. The mean operative time was 90 minutes and the mean blood loss was 28 ml per level. Preoperatively stenosis was severe at 13 levels, moderate/severe at eight, and moderate at one. Postoperatively stenosis was absent at 13 levels, mild at seven, mild/moderate at one, and moderate at one. Preoperatively degenerative spondylolisthesis was documented in eight patients, with flexion—extension radiography revealing motion in three cases. On early (3-month) postoperative x-ray films there was no evidence of progression in any case. Grade I spondylolisthesis developed postoperatively in one patient, who remained asymptomatic.

Conclusions. Minimally invasive bilateral decompression and instrumentation-assisted fusion can be successfully performed via a unilateral approach in patients with acquired spinal stenosis; the procedure can be undertaken on an outpatient basis, with reasonable operative times, minimal blood loss, and acceptable morbidity rates.
Comparison of computerized tomography and direct visualization in thoracic pedicle screw placement
Authors: Rao Ganesh , Brodke Darrel S. , Rondina Matthew , Dailey Andrew T.
Published: May 2009

Object. To validate computerized tomography (CT) scanning as a tool to assess the accuracy of thoracic pedicle screw placement, the authors compared its accuracy with that of direct visualization in instrumented cadaveric spine specimens.

Methods. A grading scale was devised to score the placement of the pedicle screw. The grades ranged from 0 to 3 depending on the extent to which the pedicle had been violated. One hundred fifty-five pedicles were fitted with instrumentation in eight cadaveric spines. A single observer graded the appearance of the screw based on CT scans (3-mm axial sections with 1-mm overlap) and direct visualization of the specimen. The authors arrived at a Kappa value of 0.51, which suggested only moderate agreement between the two measurement techniques. Whereas CT had a positive predictive value of 95%, it had a negative predictive value of 62%.

Conclusions. The authors thus conclude that although CT scanning is the most valid tool to assess the accuracy of thoracic pedicle screw placement, it tends to overestimate the number of misplaced screws.
Vertebral hemangiomas associated with familial cerebral cavernous malformation: segmental disease expression
Authors: Clatterbuck Richard E. , Cohen Bernard , Gailloud Philippe , Murphy Kieran , Rigamonti Daniele
Published: May 2009

✓ Recently, several groups of authors have described mutations in the Krevyl interaction—trapped 1 (KRIT1) gene in families in whom cerebral cavernous malformations (CCMs) are present. In a number of French kindreds harboring familial CCMs, cutaneous as well as cerebral manifestations of this autosomal-dominant disorder were demonstrated. Involvement of other tissues has been poorly described. The authors present the proband, in an affected family with a previously reported KRIT1 mutation, in whom vertebral hemangiomas in addition to cerebral and cutaneous lesions were found. One of the vertebral lesions was associated with a large cutaneous lesion. This combination of vertebral and overlying cutaneous lesions suggests segmental disease expression as the result of a second hit during development, implying loss of function as the relevant molecular pathogenic mechanism. This case illustrates that tissue involvement outside the nervous system must be considered when treating patients with familial CCMs.
Thoracic diastematomyelia with concurrent intradural epidermoid spinal cord tumor and cervical syrinx in an adult
Authors: Sheehan Jason P. , Sheehan Jonas M. , Lopes M. Beatriz , Jane John A.
Published: May 2009

✓ Diastematomyelia is a rare entity in which some portion of the spinal cord is split into two by a midline septum. Most cases occur in childhood, but some develop in adulthood. A variety of concurrent spinal anomalies may be found in patients with diastematomyelia.

The authors describe a 38-year-old right-handed woman who presented with a 7-month history of lower-extremity pain and weakness on the right side. She denied recent trauma or illness. Sensorimotor deficits, hyperreflexia, and a positive Babinski reflex in the right lower extremity were demonstrated on examination.

Neuroimaging revealed diastematomyelia extending from T-1 to T-3, an expanded right hemicord from T-2 to T-4, and a C6–7 syrinx. The patient underwent T1–3 total laminectomies, resection of the septum, untethering of the cord, and excision of the hemicord lesion. The hemicord mass was determined to be an intramedullary epidermoid cyst; on microscopic evaluation the diastematomyelia cleft was shown to contain fibroadipose connective tissue with nerve twigs and ganglion cells. Postoperatively, the right lower-extremity pain, weakness, and sensory deficits improved.

Diastematomyelia can present after a long, relatively asymptomatic period and should be kept in the differential diagnosis for radiculopathy, myelopathy, tethered cord syndrome, or cauda equina syndrome. Numerous spinal lesions can be found in conjunction with diastematomyelia. To the authors' knowledge, this is the first case in which a thoracic epidermoid cyst and cervical syrinx occurred concurrently with an upper thoracic diastematomyelia. Thorough neuraxis radiographic evaluation and surgical treatment are usually indicated.
Intramedullary plasma cell granuloma in the cervicothoracic spine
Authors: Aizawa Toshimi , Sato Tetsuro , Tanaka Yasuhisa , Kishimoto Koshi , Watanabe Mika , Kokubun Shoichi
Published: May 2009

✓ Intraspinal plasma cell granuloma, which is a nonneoplastic entity, is extremely rare. To date, only four cases have been documented in the spinal meninges. The authors report the first case of a C7—T1 intramedullary plasma cell granuloma. After excision of the lesion, the patient's gait and bladder dysfunction improved. This plasma cell granuloma initially showed no delineated mass on T1-weighted magnetic resonance (MR) images, low signal intensity on T2-weighted images, and was well enhanced after administration of gadolinium diethylenetriamine pentaacetic acid. The latter MR imaging modality should help to detect this tumorous lesion. Histologically, the granuloma needs to be distinguished from lymphoplasmacyte-rich meningioma and plasmacytoma.
Isolated inflammatory pseudotumor of the occipital condyle
Authors: Pallini Roberto , Liverana Lauretti , Maria Larocca Luigi , Cesare Colosimo , Eduardo Fernandez , Babu Ramesh
Published: May 2009

✓ Although the craniocervical junction is involved in a variety of conditions including trauma, neoplastic lesions, and inflammatory processes, isolated inflammatory conditions involving the occipital condyle exclusively are not known. The authors report this unusual condition in two cases. Unless the patient is of poor medical risk, excision of the lesion is the treatment of choice to decompress the neural structures.
Preoperative embolization and intraoperative cryocoagulation as adjuncts in resection of hypervascular lesions of the thoracolumbar spine
Authors: Nader Remi , Alford Brent T. , Nauta Haring J. W. , Crow Wayne , Vansonnenberg Eric , Hadjipavlou Alexander G.
Published: May 2009

Object. The purpose of this study was twofold. First the authors evaluated preoperative embolization alone to reduce estimated blood loss (EBL) when resecting hypervascular lesions of the thoracolumbar spine. Second, they compared this experience with intraoperative cryotherapy alone or in conjunction with embolization to minimize further EBL.

Methods. Twelve patients underwent 13 surgeries for hypervascular spinal tumors. In 10 cases the surgeries were augmented by preoperative embolization alone. In one patient, two different surgeries involved intraoperative cryocoagulation, and in one patient surgery involved a combination of preoperative embolization and intraoperative cryocoagulation for tumor resection. When cryocoagulation was used, its extent was controlled using intraoperative ultrasonography or by establishing physical separation of the spinal cord from the tumor.

In the 10 cases in which embolization alone was conducted, intraoperative EBL in excess of 3 L occurred in five. Mean EBL was of 2.8 L per patient. In one patient, who underwent only embolization, excessive bleeding (> 8 L) required that the surgery be terminated and resulted in suboptimum tumor resection. In another three cases, intraoperative cryocoagulation was used alone (in two patients) or in combination with preoperative embolization (in one patient). In all procedures involving cryocoagulation of the lesion, adequate hemostasis was achieved with a mean EBL of only 500 ml per patient. No new neurological deficits were attributable to the use of cryocoagulation.

Conclusions. Preoperative embolization alone may not always be satisfactory in reducing EBL in resection of hypervascular tumors of the thoracolumbar spine. Although experience with cryocoagulation is limited, its use, in conjunction with embolization or alone, suggests it may be helpful in limiting EBL beyond what can be achieved with embolization alone. Cryocoagulation may also assist resection by preventing spillage of tumor contents, facilitating more radical excision, and enabling spinal reconstruction. The extent of cryocoagulation could be adequately controlled using ultrasonography or by establishing physical separation between the tumor and spinal cord. Additionally, somatosensory evoked potential monitoring may provide early warning of spinal cord cooling.
Surgical treatment of spinal deformities associated with neurofibromatosis Type 1
Authors: Halmai Vilmos , Domán István , de Jonge Tamás , Illés Tamás
Published: May 2009

Object. In 10 to 50% of cases with neurofibromatosis, skeletal disorders are present, mainly as various deformities of the spine. These deformities can be divided into dystrophic and nondystrophic groups depending on the absence or presence of bone dystrophy. The nondystrophic curves are highly similar to those in idiopathic scoliosis, whereas the dystrophic curves are manifested early and, by progressing inexorably, may lead to neurological symptoms. In this article the authors report on a series of 12 patients (11 with dystrophic and one with nondystrophic deformities) who underwent surgical treatment.

Methods. In the case with a nondystrophic curve, posterolateral instrumentation-assisted fusion was performed. A curvature correction of 70% was achieved in the frontal plane, and at the 2-year follow-up examination neither bone dysplasia nor pseudarthrosis was observed. In the cases with dystrophic curves, preoperative traction for 3 weeks was applied; anterior surgical release was then performed, as was two-stage posterior instrumentation-assisted fusion. In the cases of thoracic kyphoscoliosis in which this treatment protocol was performed, the mean scoliosis correction was 66%, whereas the mean decrease in kyphotic angle was 34.5°. In the cases with thoracolumbar and lumbar curves, the mean correction in the frontal plane was 69.8°, whereas the mean preoperative lumbar kyphosis of 42° was corrected to a mean lordotic angle of 23°. Postoperatively, no hook dislocation was detected. A neurological complication was observed in one case.

Conclusions. The surgical treatment of dystrophic curves always included 360° fusion and the use of a tibial corticocancellous graft, which must be placed on the concave side of the curve in the frontal plane, the graft thereby providing biomechanical support.
Syringomyelia associated with foramen magnum arachnoiditis
Authors: Klekamp Jörg , Iaconetta Giorgio , Batzdorf Ulrich , Samii Madjid
Published: May 2009

Object. Syringomyelia is often linked to pathological lesions of the foramen magnum. The most common cause is hindbrain herniation, usually referred to as Chiari I or II malformation. Foramen magnum arachnoiditis without either Chiari I or II malformation is a rare cause of syringomyelia. The authors undertook a retrospective analysis of 21 patients with foramen magnum arachnoiditis (FMA) and syringomyelia treated between 1978 and 2000 to determine clinical course and optimum management.

Methods. In the review of records, 21 patients with FMA and syringomyelia were documented. A stable clinical course was demonstrated in three patients in whom surgery was not performed, and one patient refused surgical intervention. Seventeen patients underwent 23 operations to treat progressive neurological disease. Of these 23 operations, 18 involved opening of the foramen magnum, arachnoid dissection, and placement of a large dural graft. One patient underwent insertion of a ventriculoperitoneal shunt for treatment of accompanying hydrocephalus, one patient received a cystoperitoneal shunt for an accompanying arachnoid cyst; two syringoperitoneal and one syringosubarachnoid shunts were also inserted. Hospital and outpatient files, neuroimaging studies, and intraoperative photographic and video material were analyzed. Additional follow-up information was obtained by telephone interview and questionnaires.

Standard and cardiac-gated magnetic resonance imaging studies are the diagnostic procedures of choice in these patients. Sensory disturbances, dysesthesias, and pain were the only symptoms likely to improve after foramen magnum surgery. Motor weakness and gait disturbances, which were severe in a considerable number of patients, and swallowing disorders tended to remain unchanged. As a consequence of the rather severe arachnoid lesions in most patients, clinical recurrences were observed in 57% over a 5-year period.

Conclusions. Surgery for FMA and syringomyelia has to provide clear cerebrospinal fluid pathways between the cerebellopontine cisterns, spinal canal, and fourth ventricle. If this can be achieved successfully, the syrinx decreases in size and the clinical course of the patient may even improve. In patients with severe and widespread areas of arachnoiditis, however, multiple operations may be required at least to stabilize the clinical course.
Preliminary experience with the DOC dynamic cervical implant for the treatment of multilevel cervical spondylosis
Authors: Steinmetz Michael P. , Warbel Ann , Whitfield Melvin , Bingaman William
Published: May 2009

Object. Despite the wide use of anterior cervical instrumentation in the management of multilevel cervical spondylosis, the incidences of pseudarthrosis and instrument-related failure remain high. The use of a dynamic implant may aid in the prevention of these complications. The purpose of this study was to evaluate the DOC dynamic cervical implant in the treatment of multilevel cervical spondylosis.

Methods. The authors evaluated 34 cases in which anterior multilevel cervical decompression and fusion were performed using the DOC Ventral Cervical Stabilization System. Postoperatively, and at each follow-up visit, the sagittal angle and the degree of subsidence that developed were measured. Fusion rates and clinical outcomes were also evaluated.

The mean postoperative sagittal angle was 14° of lordosis. The mean change in the sagittal angle during the follow-up period was 0.4° of lordosis. By 6 months postoperatively some subsidence had occurred in most patients, with no subsidence occurring in only 15%. By 3 months greater than or equal to 2 mm of subsidence was demonstrated in 61% of cases. The overall fusion rate was 91%. In the majority of patients (79%) symptoms were judged to be improved or resolved.

Conclusions. The DOC dynamic cervical implant permitted controlled subsidence and prevented progression of kyphotic deformity. There was one construct failure (related to a motor vehicle accident) and an overall fusion rate of 91%. The DOC implant is a safe and effective cervical construct for multilevel spondylotic disease.
Surgical approach to anterior compression in the upper thoracic spine
Authors: Seol Ho Jun , Chung Chun Kee , Kim Hyun Jib
Published: May 2009

Object. The anterior upper thoracic spine (T1–3) is difficult to access because most neurosurgeons are unfamiliar with the anatomy. This study was performed to evaluate the different surgical options by retrospectively analyzing data on operations performed for anterior upper thoracic compression at the authors' institution.

Methods. Eighteen patients underwent surgery between November 1993 and May 2001. There were eight men and 10 women; their mean age was 55 years (range 28–80 years). All patients presented with pain and/or neurological deficits. The causes of anterior compression were diverse, although metastatic spinal tumor was most common. The approach chosen was primarily dictated by the axial involvement of the lesion. Anterior approaches, mainly the transmanubrium approach, were performed in six and posterior approaches in 12. In all cases except one, in which only an iliac bone graft was placed, instrumentation was used. The mean follow-up period was 11.4 months (range 1–57 months). One postoperative death occurred. Postoperative follow-up imaging studies, especially plain radiography, demonstrated no instrumentation failure. Improvement was shown in eight patients, an aggravation of symptoms in one, and stable clinical status in eight.

Conclusions. Decompression may be achieved on the anterior side of the upper thoracic spine if the operative approach is scrupulously chosen; this choice involves consideration of the locations of the lesion, the nature of the primary disease, and the surgery-related risk.
Quantitative anatomy of the transverse ligament tubercles
Authors: Tubbs R. Shane , Wellons John C. , Banks Jason , Blount Jeffrey P. , Oakes W. Jerry
Published: May 2009

Object. The medial tubercles of the atlas serve as the attachments of the transverse ligament and provide an important anchoring site for which no discussion of their fine anatomy is published in the literature. In this study the authors examine this anatomy along with its osseous relationships.

Methods. One hundred dry cadaveric atlantal tubercles were assessed for size and relationship to nearby anatomical osseous structures. In addition, eight cadaveric specimens were evaluated for their anatomy in this area.

All specimens exhibited atlantal tubercles for the attachment of the transverse portion of the cruciate ligament of the atlas. Right-sided tubercles tended to be of a larger caliber. Overall, right-sided vertical distances between these tubercles and the superior articular facets and inferior articular facets were greater, although distances from each tubercle to the lateral margin of the dental facets anteriorly were found to be constant, as were intertubercular distances. The mean angle formed between both tubercles and the dental facet was 75°.

Conclusions. The data derived in this study should be useful to the clinician for whom the craniocervical junction is a vital anatomical area.
Beta—tricalcium phosphate as a substitute for autograft in interbody fusion cages in the canine lumbar spine
Authors: Ohyama Takashiro , Kubo Yoshichika , Iwata Hiroo , Taki Waro
Published: May 2009

Object. An interbody fusion cage has been introduced for cervical anterior interbody fusion. Autogenetic bone is packed into the cage to increase the rate of union between adjacent vertebral bodies. Thus, donor site—related complications can still occur. In this study a synthetic ceramic, β—tricalcium phosphate (TCP), was examined as a substitute for autograft bone in a canine lumbar spine model.

Methods. In 12 dogs L-1 to L-4 vertebrae were exposed via a posterolateral approach, and discectomy and placement of interbody fusion cages were performed at two intervertebral disc spaces. One cage was filled with autograft (Group A) and the other with TCP (Group B). The lumbar spine was excised at 16 weeks postsurgery, and biomechanical, microradiographic, and histological examinations were performed.

Both the microradiographic and histological examinations revealed that fusion occurred in five (41.7%) of 12 operations performed in Group A and in six (50%) of 12 operations performed in Group B. The mean percentage of trabecular bone area in the cages was 54.6% in Group A and 53.8% in Group B. There were no significant intergroup differences in functional unit stiffness.

Conclusions. Good histological and biomechanical results were obtained for TCP-filled interbody fusion cages. The results were comparable with those obtained using autograft-filled cages, suggesting that there is no need to harvest iliac bone or to use allo- or xenografts to increase the interlocking strength between the cage and vertebral bone to achieve anterior cervical interbody fusion.
Intraoperative angiography to prevent vertebral artery injury during reduction of a dislocated hangman fracture
Authors: Takahashi Toshiyuki , Tominaga Teiji , Ezura Masayuki , Sato Kiyotaka , Yoshimoto Takashi
Published: May 2009

✓ The authors report on a 38-year-old woman with a dislocated hangman fracture associated with unilateral vertebral artery (VA) occlusion. The patient presented with a mild central cord syndrome, as well as anterior subluxation of the C-2 vertebral body upon C-3, bilateral neural arch fractures, and a unilateral locked facet joint. Digital subtraction angiography revealed occlusion of the right VA, with the posterior cerebral circulation entirely dependent on the left VA. Intraoperative angiography demonstrated that complete reduction of the dislocation would have caused severe stenosis of the left VA; partial reduction and anterior fixation were performed instead, with excellent neurological outcome. In this case, intraoperative angiography was particularly useful for preventing brain-related ischemic complications during reduction.
Spinal cord compression by multistrand cables after solid posterior atlantoaxial fusion
Authors: Sudo Hideki , Abumi Kuniyoshi , Ito Manabu , Kotani Yoshihisa , Minami Akio
Published: May 2009

✓ The sublaminar wiring procedure has been commonly used for stabilizing the atlantoaxial complex. Multistrand braided cables were introduced in the early 1990s. In previous biomechanical studies these cables were demonstrated to be superior to monofilament wires in terms of their flexibility, mechanical strength, and fatigue-related characteristics. To the authors' knowledge, they are the first to describe clinically the occurrence of delayed spinal cord compression resulting from multistrand cables after the completion of rigid spinal arthrodesis in the upper cervical spine.

Three patients underwent posterior atlantoaxial fusion in which two sublaminar multistrand cables were placed. Between 15 and 48 months postoperatively, they suffered from upper- and lower-extremity numbness as well as gait disturbance. Plain radiography and computerized tomography myelography revealed spinal cord compression caused by the sublaminar cables, although fusion was complete and physiological alignment was maintained at the fused segment. The radiographs obtained immediately after surgery demonstrated that the initial cable placement had been properly performed. The shape of the cable at the initial surgery was oval and then gradually became circular. The anterior arc of the circular shape of the cable in fact led to the spinal cord compression.

Considering the mechanism of this late complication, a cable tends to spring open because of its high flexibility and becomes circular shaped even after the complete arthrodesis. When applying multistrand cables for intersegmental fixation at the atlantoaxial complex, delayed complications related to bowing of the cables is possible.
Delayed management of traumatic bilateral cervical facet dislocation: surgical strategy
Authors: Bartels Ronald H. M. A. , Donk Roland
Published: May 2009

✓ Postinjury cervical spine instability typically requires surgical treatment in the acute or semiacute stage. The authors, however, report on three patients with older (> 8 weeks) untreated bilateral cervical facet dislocation. In two patients they attempted a classic anterior-posterior-anterior approach but failed. The misalignment in the second stage of the procedure could not be corrected, and they had to add a fourth, posterior, stage. To avoid the fourth stage, thereby reducing operating time and risk of neurological damage while turning the patient, they propose the following sequence: 1) a posterior approach to perform a complete facetectomy bilaterally with no attempt to reduce the dislocation; 2) an anterior microscopic discectomy with reduction of the dislocation and anterior fixation; and 3) posterior fixation. This sequence of procedures was successfully performed in the third patient. Based on this experience, they suggest that in cases of nonacute bilateral cervical facet dislocations the operating sequence should be posterior-anterior-posterior.
Dural arteriovenous fistula and progressive conus medullaris syndrome as complications of lumbar discectomy
Authors: Asakuno Keizoh , Kim Phyo , Kawamoto Toshiki , Ogino Masahiro
Published: May 2009

✓ A case of a dural arteriovenous fistula (DAVF) that developed at the site of nerve root sleeve damage as a result of lumbar disc extrusion is reported. A 60-year-old man who had undergone lumbar discectomy 3 years previously for severe left-sided sciatica and L5—S1 disc herniation presented with progressive gait disturbance. After the initial surgery, the symptoms resolved. Fourteen months after the operation, however, he started to experience dysesthesias in both legs and progressive gait and urinary disturbances. Physical examination revealed a weakness of the anterior tibialis and the gastrocnemius muscles, as well as decreased contractility of the anal sphincter and marked sacral hypesthesia. Magnetic resonance (MR) imaging revealed swelling and a T2 signal elongation in the conus medullaris; angiography demonstrated arteriovenous dural shunting between the left lateral sacral artery and the left S-1 radicular vein at the site of the previous operation. Surgery was conducted to excise the DAVF on the S-1 nerve root sleeve and an arterialized intradural vein on the root. The procedure resulted in resolution of the symptoms and disappearance of the abnormal angiographically and MR imaging—documented anomalies. This is the first report of a DAVF in which progressive conus myelopathy developed after a lumbar discectomy.
Spontaneous osteoporotic fractures of the sacrum causing neurological damage
Authors: Finiels Pierre-Jacques , Finiels Hélène , Strubel Denise , Jacquot Jean-Marc
Published: May 2009

✓ Although osteoporotic fractures of the sacrum seem to be a well-known entity, their associated rate of neurological complications has not been assessed in the literature. The authors report three such cases of nerve root compromise in elderly women and conduct a literature review. Based on their review, they estimate the incidence to be approximately 2%.

The true incidence is probably higher because many case reports provide only scant information on symptoms; furthermore, sphincter dysfunction and lower-limb paresthesias are the most common symptoms and can readily be overlooked or misinterpreted in elderly patients with multiple health problems. The neurological manifestations were delayed in some cases. A full recovery is the rule. The characteristics of the sacral fracture are not consistently related with the risk of neurological compromise. In most reviewed cases the authors found no displacement and in many the foramina were not involved.

The pathophysiology of the neurological manifestations remains unclear. The authors suggest that patients with sacral osteoporotic fractures should be carefully monitored for neurological manifestations.
Total cervical spondylectomy for primary osteogenic sarcoma
Authors: Cohen Zvi R. , Fourney Daryl R. , Marco Rex A. , Rhines Laurence D. , Gokaslan Ziya L.
Published: May 2009

✓ The authors describe a technique for total spondylectomy for lesions involving the cervical spine. The method involves separately staged anterior and posterior approaches and befits the unique anatomy of the cervical spine. The procedure is described in detail, with the aid of radiographs, intraoperative photographs, and illustrations. Unlike in the thoracic and lumbar spine—for which methods of total en bloc spondylectomy have previously been described—a strictly en bloc resection is not possible in the cervical spine because of the need to preserve the vertebral arteries and the nerve roots supplying the upper limbs. Although the resection described in this case is by definition intralesional, it is oncologically sound, given the development of effective neoadjuvent chemotherapeutic regimens for osteosarcoma.
Traumatic neuroma of the anterior cervical nerve root with no subjective episode of trauma
Authors: Nomura Hiroshi , Harimaya Katsumi , Orii Hisaya , Shiba Keiichiro , Ueta Takayoshi , Iwaki Toru
Published: May 2009

✓ The authors report four cases of traumatic neuroma in the cervical nerve root in patients with no history of trauma. In one case the patient presented with intractable pain in the left upper extremity and motor paresis of the left shoulder, and in another case the patient suffered neuropathic pain in the left forearm. In both cases, magnetic resonance (MR) imaging revealed an intradural extramedullary mass lesion in the ipsilateral cervical nerve root; these MR imaging signals were similar to the intensity of the spinal cord. Intraoperatively, fusiform enlargement of the anterior cervical nerve root was detected in the subarachnoid space. Histological examination showed a meandering change of axons accompanied by mild axonal swelling and a thin myelin sheath, which are consistent with the typical pathological features of traumatic neuroma. Postoperatively, pain resolved in both cases. The authors also investigated two traumatic neuromas of the anterior cervical nerve root in autopsy cases in which there was no history of trauma and no significant neurological signs suggestive of traumatic neuroma.

The authors conclude that traumatic neuroma of the anterior cervical nerve root may develop following an unnoticed minor brachial plexus injury at birth or a forgotten traction injury of the upper extremity in childhood, and the lesion may be accompanied by various case-specific clinical features.
Spinal applications of bioabsorbable implants
Authors: Vaccaro Alexander R. , Madigan Luke
Published: May 2009

✓ With the increasing use of bioabsorbable implants in a variety of clinical conditions, potential advantages in selected spinal applications are now being realized. Newer polymers with biomechanical properties relevant to the requirements of specific spinal implants and resorption rates appropriate for specific spinal applications are being developed. These new materials offer the necessary biomechanical stability of conventional spinal implants without the sequelae associated with metallic implants such as long-term loosening, implant migration, and imaging interference. At this time, the majority of clinical applications for these new polymers have involved tension band plating in the lumbar and anterior cervical spine, anterior spinal interbody reconstruction, posterior bone graft containment, and bone graft harvest site reconstruction.
Resorbable cages for spinal fusion: an experimental goat model
Authors: Wuisman P. I. J. M. , van Dijk M. , Smit T. H.
Published: May 2009

Object: A biomechanical cadaveric study and an in vivo monosegmental spinal fusion study were performed to evaluate a novel bioresorbable poly(l-lactic acid) (PLLA) cage.

Methods: The yield strength of a spinal segment was chosen as the main design parameter for the resorbable cages to be used in a goat model. In a 3-year in vivo study the authors found fusion to be significantly faster and more complete when using PLLA cages compared to titanium cages with the same dimensions. In the PLLA group, the inter-vertebral grafting height did not change and bone remodeling within the cage was completed 2 years after implantation. In terms of degradation of the PLLA, similar features were observed in vivo and in vitro.

Conclusions. Degradation was almost completed 3 years after implantation. Tissue reaction was mild during the 3-year period.
Bioabsorbable anterior lumbar plate fixation in conjunction with cage-assisted anterior interbody fusion
Authors: DiAngelo Denis J. , Scifert Jeffrey L. , Kitchel Scott , Cornwall G. Bryan , McVay Bobby J.
Published: May 2009

Object. An in vitro biomechanical study was conducted to determine the effects of anterior stabilization on cage-assisted lumbar interbody fusion biomechanics in a multilevel human cadaveric lumbar spine model.

Methods. Three spine conditions were compared: harvested, bilateral multilevel cages (CAGES), and CAGES with bioabsorbable anterior plates (CBAP), tested under flexion—extension, lateral bending, and axial rotation. Measurements included vertebral motion, applied load, and bending/rotational moments. Application of anterior fixation decreased local motion and increased stiffness of the instrumented levels. Clinically, this spinal stability may serve to promote fusion.

Conclusions. Coupled with the bioabsorbability of the plating material, the bioabsorbable anterior lumbar plating system is considered biomechanically advantageous.
Use of a resorbable sheet in iliac crest reconstruction in a sheep model
Authors: Cornwall G. Bryan , Wheeler Donna L. , Thomas Kevin A. , Taylor William R. , Turner A. Simon
Published: May 2009

Object. Iliac crest bone graft harvesting can result in major complications, the rates of which range from approximately 6 to 8%. The objective of this study was to evaluate the postoperative regeneration of iliac crest donor defects in an animal model after harvesting a full-thickness tricortical graft.

Methods. In skeletally mature sheep, a tricortical iliac crest graft was harvested. The graft sites were allowed to heal unprotected or protected with the resorbable polylactic acid sheet material, MacroPore OS Protective Sheeting. After 6 months of healing, the sites were assessed by examination of undecalcified histological sections. Histomorphometric measurements of the original defect area, the area of new bone within the defect site, and the percentage of defect filled with new bone were quantified for both control and protected groups. In all histological sections, new bone growth within the defect sites appeared normal, with no observed excessive inflammatory cells. The developing bone tissue appeared to be remodeling normally. For the unprotected sites, the area of new bone averaged 16.3 mm2 (± 7.2 mm2), and the percentage of the defect area filled with bone averaged 10.7% (± 6.5%). In the protected sites, the area of new bone averaged 64.8 mm2 (± 11.6 mm2) and the percentage of the defect area filled with bone averaged 25.9% (± 1.6%). Both differences in area of new bone growth and percentage of defect area filled were statistically significant. Literature review has indicated that regeneration of donor site defects is desirable.

Conclusions. Based on the results of the present study, MacroPore resorbable Protective Sheeting can improve bone regeneration significantly within the donor site following tricortical iliac crest graft harvesting.
Resorbable polymer implants in unilateral transforaminal lumbar interbody fusion
Authors: Lowe Thomas G. , Coe Jeffrey D.
Published: May 2009

Object. Sixty patients underwent instrumentation-assisted posterior transforaminal lumbar interbody fusion (TLIF) with resorbable polymer cages and autograft bone for degenerative disease. This article discusses the technique of TLIF and its early outcomes.

Methods. Although the follow-up period is short and results are preliminary, no adverse events or complications were attributed to the resorbable polymer.

Conclusions. Further multicenter clinical studies are underway with a minimum 2-year follow-up period chosen as an endpoint to provide insight as to the future of biodegradable polymers as spinal interbody devices.
Anterior cervical arthrodesis using DOC dynamic stabilization implant for improvement in sagittal angulation and controlled settling
Authors: Bose Bikash
Published: May 2009

Object. Placing instrumentation in the anterior cervical spine is a common procedure. The bi- and unicortical systems currently available, however, have distinct advantages and disadvantages. The author reports a prospective series in which a new dynamized anterior cervical fixation system was evaluated.

Methods. Thirty-seven patients underwent anterior cervical discectomy and fusion in which the DOC ventral cervical stabilization system was used for indications including cervical spondylotic radiculopathy, disc herniation, trauma, and myelopathy. Patients underwent anterior cervical discectomy and interbody fusion and/or corpectomy. Preoperative and postoperative clinical data included assessment of spinal cord and nerve root deficit, function, neck pain, and arm pain. Preoperative and postoperative radiographic data included sagittal angle, translation, and settling of the graft. Fusion status was determined by the presence of trabecular bridging bone on plain anteroposterior and lateral cervical radiographs.

At a mean follow-up time of 1.3 years, postoperative neck or arm pain was resolved in 52% of the patients, restriction on function was mild or absent in 88%, and fusion was successful in 80% of patients and 88% of the treated levels. There was one implant-related complication, one significant dysphagia complication, and a 10.8% donor graft site complication rate.

Conclusions. The use of this system led to a high percentage of pain relief and radiographic fusion. The sagittal angle was controlled while allowing for graft settling. There were no implant failures.
Kryorhizotomy: an alternative technique for lumbar medial branch rhizotomy in lumbar facet syndrome
Authors: Bärlocher Christian B. , Krauss Joachim K. , Seiler Rolf W.
Published: May 2009

Object. The authors conducted a prospective study to investigate the efficacy of kryorhizotomy, an alternative procedure for lumbar medial branch neurotomy, in the treatment of lumbar facet syndrome (LFS).

Methods. Fifty patients with chronic low-back pain, in whom pain was relieved by controlled diagnostic medial branch blocks of the lumbar zygapophyseal (facet) joints, underwent lumbar medial branch kryorhizotomy. Outcome was evaluated using the Visual Analog Pain Scales and assessment of work capacity. All outcome measures were repeated at 6 weeks, 6 months, and 1 year after surgery. At 1-year follow-up examination, 31 (62%) of 50 patients experienced a good response to lumbar facet kryorhizotomy. Good results with pain relief of 50% or more were obtained in 85% of patients without previous spinal surgery but only in 46% who had undergone previous spinal surgery. This difference was statistically significant. In five patients (16%) in whom a good initial benefit was observed but who experienced increased pain within 6 weeks after kryorhizotomy, the beneficial result was regained after an early repeated procedure. There were no side effects. Overall, 19 (38%) of 50 procedures were not considered successful. In six of these 19 cases a rigid stabilization of the involved segment provided permanent pain relief.

Conclusions. Based on this study, patients with LFS who have not undergone previous spinal surgery benefit significantly from percutaneous lumbar kryorhizotomy. Kryorhizotomy, which has virtually no risk, seems to be a valuable alternative technique to lumbar medial branch neurotomy.
Inclination of the odontoid process in the pediatric Chiari I malformation
Authors: Tubbs R. Shane , Wellons John C. , Blount Jeffrey P. , Grabb Paul A. , Oakes W. Jerry
Published: May 2009

Object. The quantitative analysis of odontoid process angulation has had scant attention in the Chiari I malformation population. In this study the authors sought to elucidate the correlation between posterior angulation of the odontoid process and patients with Chiari I malformation.

Methods. Magnetic resonance images of the craniocervical junction obtained in 100 children with Chiari I malformation and in 50 children with normal intracranial anatomy (controls) were analyzed. Specific attention was focused on measuring the degree of angulation of the odontoid process and assigning a score to the various degrees. Postoperative outcome following posterior cranial fossa decompression was then correlated to grades of angulation. Other measurements included midsagittal lengths of the foramen magnum and basiocciput, the authors' institutions' previously documented pB—C2 line (a line drawn perpendicular to one drawn between the basion and the posterior aspect of the C-2 body), level of the obex from a midpoint of the McRae line, and the extent of tonsillar herniation.

Higher grades of odontoid angulation (retroflexion) were found to be more frequently associated with syringomyelia and particularly holocord syringes. Higher grades of angulation were more common in female patients and were often found to have obices that were caudally displaced greater than three standard deviations below normal.

Conclusions. These results not only confirm prior reports of an increased incidence of a retroflexed odontoid process in Chiari I malformation but quantitatively define grades of inclination. Grades of angulation were not found to correlate with postoperative outcome. It is the authors' hopes that these data add to our current limited understanding of the mechanisms involved in hindbrain herniation.
Enhanced primary stability through additional cementable cannulated rescue screw for anterior thoracolumbar plate application
Authors: Schultheiss Markus , Claes Lutz , Wilke Hans-Joachim , Kinzl Lothar , Hartwig Erich
Published: May 2009

Object. The authors conducted a study to investigate the biomechanical in vitro influence of a new anchorage system for fixation of anterior stabilization devices and the possibility of using additional cement after screw insertion to compensate for poor bone quality. The incidence of osteoporosis-related fractures has increased nearly twofold in the last decade. Because of problems associated with anterior screw fixation such as loosening, mechanical failure, and the weakness of osteoporotic bone, current surgical treatments of vertebral body (VB) fractures are problematic. This is due to poor fixation strength of anterior screws in the adjacent segments.

The aim of this study was to determine whether a new cemented and uncemented VB screw provides improved primary stability following placement of anterior instrumentation in cases of fracture.

Methods. The primary stability-related parameters of a new uncemented/cemented screw were compared with those of conventional monocortical screw fixation in a burst fracture model in which strut graft and anterior overbridging instrumentation were used.

The use of the new uncemented screw improved the range of motion (ROM) of the stabilized spine in flexion—extension by approximately 22%, in rotation by 20%, and in lateral bending by 15%. Additional cementation improved the ROM by approximately 41% in flexion—extension, 32% in rotation, and 30% in lateral bending compared with conventional monocortical screw fixation.

Conclusions. The new cannulated screw improves fixation strength and primary stability parameters. It is useful in the initial treatment of fractures in cases of poor bone quality and as a rescue device if previously inserted screws do not remain securely in place.
Age-related changes in expression of transforming growth factor-β and receptors in cells of intervertebral discs
Authors: Matsunaga Shunji , Nagano Satoshi , Onishi Toshiyuki , Morimoto Norio , Suzuki Shusaku , Komiya Setsuro
Published: May 2009

Object. The authors conducted a study to determine age-related changes in expression of transforming growth factor (TGF)—β1, —β2, —β3, and Type I and Type II receptors in various cells in the nucleus pulposus and anulus fibrosus.

Immunolocalization of TGFβs and Type I and II receptors was examined during the aging process of cervical intervertebral discs in senescence-accelerated mice (SAM). The TGFβ family has important roles for cellular function of various tissues. Its role in disc aging, however, is unknown. Detailed information on the temporal and spatial localization of TGFβs and their receptors in discs is required before discussing introduction of them clinically into the intervertebral disc.

Methods. Three groups of five SAM each were used. The groups of SAM were age 8, 24, and 50 weeks, respectively. Hematoxylin and eosin staining and immunohistochemical study involving specific antibodies for TGFβ1, -β2, -β3, and Types I and II TGF receptors were performed.

Intervertebral discs exhibited degenerative change with advancing age. The TGFβs and their receptors were present in the fibrocartilaginous cells within the anulus fibrosus and notochord-like cells within the nucleus pulposus of young mice. Expression of TGFβs and Type I and Type II receptors changed markedly in the cells within the anulus fibrosus during the aging process.

Conclusions. The TGFβs and their receptors were present in cells within the nucleus pulposus and the anulus fibrosus of young mice, and their expression decreased with age.