bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcome in neurologically impaired patients with craniovertebral junction tuberculosis: results of combined anteroposterior surgery
Authors: Arunkumar Moses Joseph , Rajshekhar Vedantam
Published: May 2009

Object. The authors studied the immediate and long-term outcome after transoral decompression, occipitocervical fusion, and antituberculous therapy (ATT) in patients who had neurological deficits due to craniovertebral junction (CVJ) tuberculosis.

Methods. In this retrospective study, the authors reviewed the management and outcome in nine consecutive patients in whom features of spinal cord compression were observed and CVJ tuberculosis was diagnosed between 1993 and 1999. They ranged in age from 9 to 55 years. Onset of symptoms was acute or subacute and rapidly progressive (median 4 months, range 1–12 months). Patients presented with neck pain (89%), progressive limb weakness (89%), sensory symptoms (22%), and urinary dysfunction (33%). The mean preoperative functional grade based on the Nurick Scale was 3.4 (range 1–5). The disease caused reducible atlantoaxial dislocation (AAD) in three patients (33%), irreducible AAD in two (22%), basilar impression (BI) in one (11%), AAD with BI in one (11%), and C-2 vertebral body (VB) destruction without dislocation in two (22%). Surgery was performed in all cases. Five patients (56%) underwent transoral odontoidectomy, two (22%) transoral decompression of retropharyngeal abscess and granulation tissue, and two (22%) transoral decompression of abscess and diseased parts of the C-2 VB. All patients then underwent occipitocervical (occiput—C3) fusion in which a contoured Steinmann pin and iliac bone grafts were used.

Postoperatively, ATT was prescribed for 18 months. In the immediate postoperative period, function in these patients improved from a mean Nurick grade of 3.4 to 2.3 (p < 0.01). At long-term follow-up examination (median 18.8 months, range 7–46 months) function improved from a mean Nurick grade of 3.4 to 0.3 (range 0–2) (p < 0.001).

Conclusions. Patients with CVJ tuberculosis with features of cervical myelopathy are ideally managed with transoral decompressive procedures followed by occipitocervical fusion because this therapy provides immediate neurological improvement, stability, and allows early mobilization. The long-term prognosis in patients with this disease is excellent provided it is treated with appropriate surgical intervention(s) and with adequate duration of ATT.
Effects of decreasing endotracheal tube cuff pressures during neck retraction for anterior cervical spine surgery
Authors: Ratnaraj Jebadurai , Todorov Alexandre , McHugh Tom , Cheng Mary Ann , Lauryssen Carl
Published: May 2009

Object. The authors' goal was to determine whether the incidence of postoperative sore throat, hoarseness, and dysphagia associated with anterior spine surgery is reduced by maintaining endotracheal tube cuff pressure (ETCP) at 20 mm Hg during the period of neck retraction.

Methods. Fifty-one patients scheduled for anterior cervical spine surgery were enrolled. After intubation, ETCP was adjusted to 20 mm Hg in all patients. Following placement of neck retractors, ETCP was measured. Patients were randomized to a control (no adjustment) or treatment group (ETCP adjusted to 20 mm Hg). A blinded observer questioned the patients about the presence of sore throat, dysphagia, and hoarseness at 1 hour, 24 hours, and 1 week postoperatively.

No differences between groups at 1 hour postoperatively were demonstrated. At 24 hours, 51% of patients in the treatment group complained of sore throat compared with 74% of control patients (p < 0.05). Sixty-five percent of the women experienced sore throat compared with 35% of the men (p < 0.05). At 24 hours, longer retraction time correlated with development of dysphagia (p < 0.05, r2 = 0.61). At 24 hours, hoarseness was present in 65% of women and 20% of men (p < 0.05).

Conclusions. The results of this study suggest the following three predictors of postoperative throat discomfort following anterior cervical spine surgery in which neck retraction is performed: increased ETCP during neck retraction (sore throat), neck retraction time (dysphagia), and female sex (sore throat and hoarseness). The simple maneuver of decreasing ETCP to 20 mm Hg may be helpful in improving patient comfort following anterior cervical spine surgery.
Dorsal root entry zone microcoagulation for spinal cord injury—related central pain: operative intramedullary electrophysiological guidance and clinical outcome
Authors: Falci Scott , Best Lavar , Bayles Rick , Lammertse Dan , Starnes Charlotte
Published: May 2009

Object. Surgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically resulted in modest outcomes. A review of the literature indicates that fair to good relief of pain is achieved in approximately 50% of patients when an empirical procedure is performed. This study was undertaken to determine if intramedullary electrical guidance in DREZ lesioning could improve outcomes in patients with SCI-induced central pain. Additionally, electrical data were used to determine if the spinal cord could be somatotopically mapped with regard to this pain of central origin.

Methods. Forty-one patients with traumatic SCI and intractable central pain underwent DREZ lesioning in which intramedullary electrical guidance was conducted. In nine patients, recording of DREZ-related spontaneous electrical hyperactivity guided the lesioning process. In 32 patients, recording of DREZ-induced evoked electrical hyperactivity during transcutaneous C-fiber stimulation (TCS) additionally guided lesioning. The follow-up period ranged from 1 to 7 years. The analyzed electrical data allowed for somatotopic mapping of the spinal cord.

Conclusions. Intramedullary electrical guidance of DREZ lesioning substantially improves pain outcomes in patients with traumatic SCI—induced central pain, compared with an empiric technique. The best outcome occurs when DREZ-related spontaneous electrical hyperactivity and evoked hyperactivity during TCS are both used to guide the DREZ lesioning procedure. With such guidance, 100% relief of pain was achieved in 84% of patients and 50 to 100% relief of pain in 88%. Somatotopic mapping of the electrical data led to a proposed pain mechanism for below-level pain, implicating the sympathetic nervous system.
A new denervation procedure for idiopathic cervical dystonia
Authors: Taira Takaomi , Kobayashi Tomonori , Takahashi Kenji , Hori Tomokatsu
Published: May 2009

Object. The Bertrand selective peripheral denervation for cervical dystonia (CD) has been well described, and its effectiveness and safety are established. It is, however, always accompanied by postoperative sensory loss in the C-2 region. Intraoperative bleeding from epidural venous plexuses may also be problematic. The authors developed a new denervation procedure with which to avoid such complications and compared the surgery-related results with those of the traditional Bertrand operation.

Methods. The new procedure consists of intradural rhizotomy of the anterior C-1 and C-2 nerve roots, extradural peripheral ramisectomy from C-3 to C-6, and selective section of peripheral branches of the accessory nerve to the sternocleidomastoid muscle. This procedure was performed in 30 patients (Group A). The results of this procedure were compared with those obtained in a matched group of 31 patients in the authors' series who underwent Bertrand denervation (Group B).

Changes of CD rating score at 6-month follow up did not differ between the two groups. In one patient in Group A a C-2 sensory deficit was found, whereas C-2 sensory deficits were demonstrated in all the patients in Group B. No patients in Group A and four patients in Group B experienced occipital neuralgia. The operative time was significantly shorter in Group A. The mean intraoperative blood loss was 115 ± 30 ml (± standard deviation) in Group A and 233 ± 65 ml in Group B (p < 0.005).

Conclusions. Although symptomatic improvement is the same after the Bertrand operation, the authors' new procedure for CD was associated with a lower incidence of complications and significant decrease of intraoperative blood loss.
Selective peripheral denervation for spasmodic torticollis: 13-year experience with 155 patients
Authors: Braun Veit , Richter Hans-Peter
Published: May 2009

Object. Botulinum toxin injections are the best therapeutic option in patients with spasmodic torticollis. Although a small number of patients do not benefit from such therapy, the majority respond well but may develop antibodies to the toxin after repeated applications. In those termed primary nonresponders, no improvement related to botulinum toxin has been shown. In patients in whom no response was shown and those in whom resistance to the therapy developed, selective peripheral denervation is a neurosurgical option.

Methods. Between June 1988 and August 2001, 155 patients underwent selective peripheral denervation. Surgery was performed at a mean of 8.5 years after the onset of symptoms (range 0.5–37 years). The mean age of the patients at the onset of dystonia was 39.7 years (range 17–77 years). For evaluation of results, patients' responses were assessed. Results were obtained in 140 patients in whom the follow-up period ranged from 3 to 124 months (mean 32.8 months): 18 reported complete relief of their symptoms, 50 significant relief, and 34 moderate relief; 19 noted only minor relief and the remaining 19 no improvement. The results differ substantially when compared with those previously demonstrated in patients who received botulinum toxin injections. Although 80% of the secondary nonresponders were satisfied with the result of surgery, only 62% of the primary nonresponders considered the operation helpful. There were no major side effects. The recurrence rate was 11%.

Conclusions. The injection of botulinum toxin should be the first-choice treatment. If surgery is required, selective peripheral denervation provides the best results and has the fewest side effects compared with all surgical options.
Fractures of the thoracolumbar spine complicating ankylosing spondylitis
Authors: Hitchon Patrick W. , From Aaron M. , Brenton Matthew D. , Glaser John A. , Torner James C.
Published: May 2009

Object. In this clinical review of ankylosing spondylitis, the authors emphasize the fragility of the spine and the degree of neurological deficit that can result from minor injury. The management of thoracolumbar fractures complicating ankylosing spondylitis is discussed.

Methods. Six thoracic and five lumbar fractures were identified in a review of patients in whom ankylosing spondylitis had been diagnosed. Nine fractures were associated with an extension deformity. The mechanism of injury was regarded as major in three and minor in eight.

The mean age in patients suffering fractures after minor traumatic injury was 59.6 ± 14.5 years (± standard deviation), whereas the mean age in patients suffering fractures after major traumatic injury was 49.3 ± 10.1 years. Two patients were treated with bedrest and brace therapy, and nine underwent instrument-assisted fusion. Postinjury neurological deficits were demonstrated in six patients, in three of whom neurological improvement was observed.

Conclusions. Patients with ankylosing spondylitis are at risk of injury, particularly extension fractures of the thoracic and lumbar spine. The incidence of trauma-induced neurological deficit is by no means negligible. Management consists of surgery in patients with vertebral instability and neural compression, and recumbency in those with stable fractures.
Arachnoiditis ossificans of the cauda equina
Authors: Faure Alexis , Khalfallah Mansour , Perrouin-Verbe Brigitte , Caillon Florence , Deschamps Cedric , Bord Eric , Mathe Jean-François , Robert Roger
Published: May 2009

✓ The authors describe a case of arachnoiditis ossificans (AO) of the cauda equina. The lesion is a rare pathological entity usually confined to the thoracic and high lumbar regions that can cause progressive spinal cord and cauda equina compression, inducing severe neurological deterioration. The authors analyze the clinical symptoms, radiological features, histological data, and treatment options relating to this case and 13 others described in the literature; additionally, they consider the possible mechanisms responsible for ossification of the leptomeninges. Although clustered arachnoidal cells are usually implicated in its pathogenesis, an environment induced by arachnoiditis and disturbed cerebrospinal fluid flow appears to be a more important factor. A therapeutic strategy is proposed for AO for which no effective treatment currently exists.
Conus medulla—cauda compression from nerve root hypertrophy in a child with Dejerine—Sottas syndrome: improvement with laminectomy and duraplasty
Authors: Kleopa Kleopas A. , Sutton Leslie N. , Ong Joseph , Tennekoon Gihan , Telfeian Albert E.
Published: May 2009

✓ This 7-year-old boy with Dejerine—Sottas syndrome caused by a mutation in the myelin protein zero gene began to suffer rapid deterioration with increasing leg weakness, loss of the ability to ambulate, and bowel and bladder incontinence. Magnetic resonance imaging of the spine revealed nerve root hypertrophy resulting in compression of the conus medullaris and cauda equina. Decompressive surgery was successful in reversing some of his deficits.
Late recovery following spinal cord injury
Authors: McDonald John W. , Becker Daniel , Sadowsky Cristina L. , Jane John A. , Conturo Thomas E. , Schultz Linda M.
Published: May 2009

✓ The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as “activity-based recovery” was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5–8 years after injury), the patient's condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5–7/112 to 58–77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3–5), extensor carpi radialis (C-6), and vastus medialis (L2–4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level.

The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.
Degenerative lumbar spondylolisthesis—induced radicular compression: nonfusion-related decompression in selected patients without hypermobility on flexion—extension radiographs
Authors: Kristof Rudolf A. , Aliashkevich Ales F. , Schuster Michael , Meyer Bernhard , Urbach Horst , Schramm Johannes
Published: May 2009

Object. The authors conducted a study to determine the results of decompressive surgery without fusion in selected patients who presented with radicular compression syndromes caused by degenerative lumbar spondylolisthesis and in whom there was no evidence of hypermobility on flexion—extension radiographs.

Methods. The medical records and radiographs obtained in 49 patients were reviewed retrospectively. Clinical status was quantified by summing self-assessed Prolo Scale scores. All 49 patients (55% female, mean age 68.7 years) presented with leg pain accompanied by lumbalgia in 85.7% of the cases. Preoperatively the median sum of Prolo Scale scores was 4. The mean preoperative degree of forward vertebral displacement was 13.5% and was located at L-4 in 67% of the cases. Osseous decompression alone was performed in 53%, and an additional discectomy at the level of displacement was undertaken in the remaining patients because of herniated discs. Major complications (deep wound infection) occurred in 2%. During a mean follow-up period of 3.73 years, 10.2% of the patients underwent instrumentation-assisted lumbar fusion when decompression alone failed to resolve symptoms. At last follow up the median overall Prolo Scale score was 8. Excellent and good results were demonstrated in 73.5% of the patients. Prolonged back pain (r = 0.381) as well as the preoperative degree of displacement (r = 0.81) and disc space height (r = 0.424) influenced outcome (p ≤ 0.05); additional discectomy for simultaneous disc herniation at the displaced level did not influence outcome (p > 0.05).

Conclusions. These results appear to support a less invasive approach in this subgroup of elderly patients with degenerative lumbar spondylolisthesis—induced radicular compression syndromes and without radiographically documented hypermobility. Additional discectomy for simultaneous disc herniation of the spondylolisthetic level did not adversely influence the outcome. Complication rates are minimized and fusion can eventually be performed should decompression alone fail. A prospective controlled study is required to confirm these results.
Percutaneous transpedicular vertebroplasty with calcium phosphate cement in the treatment of osteoporotic vertebral compression and burst fractures
Authors: Nakano Masato , Hirano Norikazu , Matsuura Kousou , Watanabe Hiroki , Kitagawa Hideki , Ishihara Hirokazu , Kawaguchi Yoshiharu
Published: May 2009

Object. Osteoporotic vertebral fractures occasionally lead to late-onset collapse, kyphosis, persistent back pain, and disability. The authors describe a series of patients in whom they performed percutaneous vertebroplasty by using calcium phosphate cement (CPC) to obtain early pain relief and improve the integrity of the osteoporotic vertebral body (VB).

Methods. Between August 2000 and February 2001, they performed 17 percutaneous transpedicular CPC-assisted vertebroplasty procedures in 16 patients who harbored thoracic or lumbar osteoporotic vertebral fractures. Following repositioning and curettage of the pathological soft tissues, CPC-assisted vertebroplasty was percutaneously performed in four patients with osteoporotic burst fracture and pseudarthrosis (Procedure A). In situ CPC-assisted vertebroplasty was performed in 12 patients with fresh vertebral compression fractures due to osteoporosis (Procedure B). Back pain and low-back pain were evaluated using a visual analog scale (VAS). The deformity index of the VB was measured on a lateral radiograph as the ratio of the VB's height (sum of measurements at anterior, middle, and posterior regions) to its longitudinal diameter. Based on VAS scores, pain was decreased in all patients immediately after surgery, and pain relief was maintained at the last follow up. The mean preoperative deformity index score of the VB was 1.43 in Procedure A and 1.67 in Procedure B; postoperatively scores improved to 1.59 and 1.93, respectively. At the 6-month follow-up examination, the mean deformity index score rebounded to 1.52 in Procedure A and 1.79 in Procedure B. Bone union was documented in all patients. Complications, such as a temporary respiratory insufficiency and a small amount of CPC leakage into the spinal canal, were observed in patients who underwent Procedure B.

Conclusions. Percutaneous transpedicular CPC-assisted vertebroplasty is a minimally invasive procedure that provides early relief of pain and prevents vertebral collapse and pseudarthrosis in patients with osteoporotic vertebral fracture.
Hydroxyapatite laminar spacers and titanium miniplates in cervical laminoplasty
Authors: Goto Takeo , Ohata Kenji , Takami Toshihiro , Nishikawa Misao , Tsuyuguchi Naohiro , Morino Michiharu , Matusaka Yasuhiro , Nishio Akimasa , Inoue Yuichi , Hara Mitsuhiro
Published: May 2009

Object. The authors describe a new surgical technique for cervical laminoplasty that was performed in 25 patients. The posterior elements along with the various ligaments are removed en bloc and are stabilized in a lift-up position by placing hydroxyapatite (HA) laminar spacers and titanium miniplates and screws. The procedure and clinical results are discussed.

Methods. The posterior spinal elements, including the lamina(e), spinous process(es), and various attached ligaments, are removed en bloc by incising the lamina in its lateral aspect. Trapezoid-shaped HA spacers are placed between the cut ends of the laminae or between the laminae and lateral masses bilaterally at each level. Malleable titanium miniplates and screws are used for fixation of the spacers. The fixation of transected laminae was judged to be successful. Postoperative care included application of a soft neck collar for 1 week but no further restriction of activity. Surgery-related outcome was assessed in the 21 patients who attended more than 6 months of follow up after laminoplasty. There were 18 men and three women who ranged in age from 27 to 81 years. Cervical stenotic myelopathy was demonstrated in 15 patients who underwent decompressive and expansive laminoplasty, and spinal tumors were documented in six patients who underwent a nonexpansive laminoplasty. Postoperative and follow-up computerized tomography scans demonstrated no hardware failure. Bone formation around the spacers was observed either at 6- or at 9-month follow-up examination in all 21 patients. Fusion of the reconstructed laminae was found to be completed at 12 months in all 18 patients able to attend follow up for this duration. Spinal alignment and the range of motion of the cervical spine were well preserved. In patients with stenotic cervical myelopathy, neurological and anatomical outcome of canal expansion were satisfactory.

Conclusions. This technique enables rigid laminoplasty while maintaining anatomical and biomechanical integrity of posterior elements of cervical spine. Expansive and nonexpansive laminoplasty procedures are possible.
Biomechanical properties of expander compared with conventional screws
Authors: Rassi-Neto Aziz , Shimano Antonio
Published: May 2009

Object. A pullout strength biomechanical study was performed in 20 fresh swine vertebral bodies in which titanium expander (Group 1) and conventional screws (Group 2) were placed.

Methods. The screws were inserted into the anterosuperior portion of the anterior spine, and assessment was performed after application of loads. The expander screw is composed of two parts: 1) a cover with an external portion comprising tight thin threads; and 2) a compact internal screw inserted through the cover that allows expansion. In the comparative study between the screws in Groups 1 and 2 maximum load was assessed, and the intergroup difference was significant (p = 0.00001 [t-test]); regarding load at the elasticity threshold, a significant difference was also observed (p = 0.0063). With regard to rigidity (stiffness), there was a tendency in both groups toward significance (p = 0.069). With regard to absorbed energy in the elastic phase, statistical analysis showed a significant intergroup difference (p = 0.00439). The expander screw showed a greater load-bearing capacity than the conventional screw. Adhesion to bone in relation to the applied load and displacement was greater (significant tendency) in the expander screw group than in the conventional screw group.

Conclusions. The expander screws exhibited a greater capacity to absorb energy in the elastic phase. They adhered better to bone, were easy to insert, and, if necessary, were simple to remove.
Syringomyelia caused by loosening of multistrand cables following C1–2 Brooks-type fusion in the rheumatoid cervical spine
Authors: Mizutani Jun , Tsubouchi Shunji , Fukuoka Muneyoshi , Otsuka Takanobu , Matsui Nobuo
Published: May 2009

✓ The authors report a very rare case of syringomyelia caused by loosening of multistrand cable wires following C1–2 Brooks-type fusion in a 36-year-old woman with a 13-year history of rheumatoid arthritis (RA). The syrinx vanished immediately after removal of the cables, and 2 years later no recurrence of symptoms or deterioration has occurred. The authors contend that multistrand titanium cables should not be used to fix a graft-assisted C1–2 construct in patients with RA, although this material is good for fixing rods. The phenomenon observed in this case adds to our understanding of the pathogenesis of noncommunicating syringomyelia.
Thoracic idiopathic spinal cord herniation at the vertebral body level: a subgroup with a poor prognosis?
Authors: Barbagallo Giuseppe M. V. , Marshman Laurence A. G. , Hardwidge Carl , Gullan Richard W.
Published: May 2009

✓ The authors present two cases of thoracic idiopathic spinal cord herniation (TISCH) occurring at the vertebral body (VB) level in whom adequate surgical reduction failed to reverse symptoms. In the second case, in which TISCH occurred into a VB cavity, presentation was atypical (subacute spinal cord syndrome) and there was persistent postoperative deterioration.

In both cases, adequate surgical reduction was achieved via a posterior midthoracic laminectomy, and reduction was maintained by closure of the anterior dural defect by using prosthetic material.

Thoracic idiopathic spinal cord herniation occurring at a VB level may be technically well treated by surgical reduction, but the outcome appears less predictable. Herniation that occurs directly into a VB cavity may form a distinct subgroup in which the presentation is atypical and the prognosis worse.
A bone and cable girth-hitch technique for atlantoaxial fusion in pediatric patients
Authors: Brockmeyer Douglas L.
Published: May 2009

✓ A new technique for performing a posterior rib and multistranded cable atlantoaxial fusion in children is described. The technique has been used successfully, in two patients 22 and 18 months of age, respectively. In both cases, fusion was used to augment C1–2 transarticular screw fixation, and solid arthrodesis was achieved without a halo orthosis.
Use of polylactide resorbable film as an adhesion barrier
Authors: Welch William C. , Thomas Kevin A. , Cornwall G. Bryan , Gerszten Peter C. , Toth Jeffrey M. , Nemoto Edwin M. , Turner A. Simon
Published: May 2009

Object. The present investigation evaluates two thicknesses of a resorbable polylactic acid (PLA) barrier film as an adhesion barrier to posterior spinal scar formation.

Methods. A readily contourable, thin film was placed directly over the dura. The thick film was placed above the lamina defect to act as a physical barrier inhibiting the prolapse of soft tissue into the epidural space. Through a combination of gross dissection with and without scar scores, quantitative analysis of collagen adjacent to the scar site, and histological evaluation, the resorbable adhesion barrier membranes were found to be effective treatment for reduction of posterior adhesions.

Conclusions. The gross dissection demonstrated that both thicknesses of resorbable PLA barrier films created a controlled dissection plane, facilitated access to the epidural space, and provided a reduction in the tissue adherent to the dura.
Evaluation of 70/30 poly (l-lactide-co-d,l-lactide) for use as a resorbable interbody fusion cage
Authors: Toth Jeffrey M. , Estes Bradley T. , Wang Mei , Seim Howard B. , Scifert Jeffrey L. , Turner A. Simon , Cornwall G. Bryan
Published: May 2009

Object. Titanium lumbar interbody spinal fusion devices are reported to be 90% effective in cases requiring single-level lumbar interbody arthrodesis, although radiographic determination of fusion has been debated.

Methods. Using blinded radiographic, biomechanical, histological, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(l-lactide-co-d,l-lactide) interbody fusion device packed with autograft or recombinant human bone morphogenetic protein—2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologically confirmed fusion was demonstrated at 3 months to 24 months postimplantation. Device degradation was associated with a mild to moderate chronic inflammatory response at all postoperative sacrifice times.

Conclusions. Use of this material in interbody fusion may be a viable alternative to metals.
Feasibility of a resorbable anterior cervical graft containment plate
Authors: Ames Christopher P. , Cornwall G. Bryan , Crawford Neil R. , Nottmeier Eric , Chamberlain Robert H. , Sonntag Volker K. H.
Published: May 2009

✓ In this article the authors review the history of anterior cervical plating for one- and two-level discectomy for degenerative disease and provide background justification for the design and testing of a cervical plate composed of a resorbable material. The design of the plate is discussed with special reference to modifications of its design and tools compared with metallic plates that are necessary because of the different mechanical properties of the less rigid material. The cadaveric and animal in vivo testing methodologies are described, and a novel testing method for reliably quantifying graft containment is also described. Data from a representative sample are presented. Advantages and disadvantages of resorbable plating are discussed.
Resorbable posterolateral graft containment in a rabbit spinal fusion model
Authors: Poynton Ashley R. , Zheng Fengyu , Tomin Emre , Lane Joseph M. , Cornwall G. Bryan
Published: May 2009

Object. The authors studied the effect of a resorbable graft containment device in a rabbit posterolateral lumbar spinal fusion model.

Methods. Twenty rabbits were divided into four groups: autologous bone graft (ABG), ABG with the MacroPore containment device (ABG + MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM + MP). Fusion mass was assessed at 6 weeks with high-resolution radiography and volumetric computerized tomography. The graft containment device was associated with alteration of the fusion mass structure and significant enhancement of fusion mass volume (ABG versus ABG + MP, p = 0.027; DBM versus DBM + MP, p = 0.043).

Conclusions. A bioabsorbable protective graft containment device successfully enhanced posterolateral spinal fusion mass volume.
Applications of a resorbable interbody spacer in posterior lumbar interbody fusion
Authors: Alexander Joseph T. , Branch Charles L. , Subach Brian R. , Haid Regis W.
Published: May 2009

✓ Polyhydroxy acids are a promising class of resorbable materials with potential applications in spinal surgery. One such polymer, MacroPore (MacroPore Biosurgery, Inc.), offers a balance of strength, predictable degradation, lack of stimulus of foreign body reaction, and biocompatibility with neural tissue. MacroPore can be formed into an array of shapes and can be manufactured, sterilized, and stored using conventional techniques. Limited clinical experience has been gained with resorbable implants used as load-sharing devices in a posterior lumbar interbody fusion construct.
Use of a bioabsorbable anterior cervical plate in the treatment of cervical degenerative and traumatic disc disruption
Authors: Vaccaro Alexander R. , Carrino John A. , Venger Benjamin H. , Albert Todd , Kelleher Peter M. , Hilibrand Alan , Singh Kush
Published: May 2009

Object. Anterior cervical discectomy and fusion (ACDF) is a widely accepted treatment for anterior degenerative or traumatic instability of the cervical spine. To reduce or eliminate complications such as implant migration and failure, imaging degradation, and fusion stress shielding that are occasionally associated with spinal instrumentation, attention has been given to the use of bioresorbable anterior cervical plate (ACP) devices. This paper is a preliminary report of a retrospective series in which a resorbable mesh and screw system was used for graft containment in single-level ACDF.

Methods. A review of patient charts and imaging studies was conducted to determine functional outcome, fusion success, and potential soft-tissue reaction to implant resorption. Nine patients with a cervical degenerative disc disease or traumatic disc disruption were treated between October 2001 and March 2002. Follow up averaged 206 days. Eight patients were found to have an excellent result, one patient had a good result, and no patients had a satisfactory or poor result. At the time of follow-up examination, 77% of patients were found to have a radiographically solid fusion. The two patients without a solid fusion were examined only an average 8 months postoperatively and manifested no symptoms related to fusion nonhealing. No significant soft-tissue reaction was noted clinically or radiographically in any of the patients.

Conclusions. The results of this preliminary study indicate that bioresorbable ACP systems for single-level ACDF are both safe and effective.
New directions in bioabsorbable technology
Authors: Warren Stephen M. , Hedrick Marc H. , Sylvester Karl , Longaker Michael T. , Chen Constance M.
Published: May 2009

✓ Generating replacement tissues requires an interdisciplinary approach that combines developmental, cell, and molecular biology with biochemistry, immunology, engineering, medicine, and the material sciences. Because basic cues for tissue engineering may be derived from endogenous models, investigators are learning how to imitate nature. Endogenous models may provide the biological blueprints for tissue restoration, but there is still much to learn. Interdisciplinary barriers must be overcome to create composite, vascularized, patient-specific tissue constructs for replacement and repair. Although multistep, multicomponent tissue fabrication requires an amalgamation of ideas, the following review is limited to the new directions in bioabsorbable technology. The review highlights novel bioabsorbable design and therapeutic (gene, protein, and cell-based) strategies currently being developed to solve common spine-related problems.
Ventral correction of postsurgical cervical kyphosis
Authors: Steinmetz Michael P. , Kager Christopher D. , Benzel Edward C.
Published: May 2009

Object. Cervical kyphotic deformation may develop after surgery involving either the ventral or dorsal approach. Regardless of the cause, the development of a cervical kyphotic deformity should be avoided, if possible, and corrected if present, when appropriate. The authors describe their experience with a technique for the ventral correction of iatrogenic (postoperative) cervical kyphosis.

Methods. A retrospective review of cases involving correction of postoperative iatrogenic cervical kyphosis via an ventral approach was performed. The authors conducted an ventral approach to kyphosis correction. The procedure required specific head positioning (in extension), convergent distraction pins, and an ventrally placed implant (axially dynamic when appropriate) with multiple points of fixation including at least one point of intermediate fixation. The pre- and postoperative sagittal angle and clinical status were evaluated.

During a nearly 14-month period, 12 patients met the inclusion criteria. Ten patients underwent a minimum of 6 months of follow up. They comprised the study population. Most patients presented with mechanical neck pain as part of their symptom profile. The mean magnitude of deformity correction (pre- to postoperative) was 20° of lordosis. The mean postoperative sagittal angle was 6° of lordosis. The mean change in the sagittal angle during the follow-up period was 2.2° of lordosis.

Conclusions. The ventral approach to correction of cervical deformity led to the achievement of lordosis in all but one patient. This posture was effectively maintained during the follow-up period. All patients exhibited improvement postoperatively; three experienced complete resolution of their preoperative symptoms. When symptoms are related to postsurgical kyphosis, deformity correction should be considered. Such a procedure may be performed effectively via an ventral approach in most circumstances.
Percutaneous vertebroplasty and kyphoplasty for painful vertebral body fractures in cancer patients
Authors: Fourney Daryl R. , Schomer Donald F. , Nader Remi , Chlan-Fourney Jennifer , Suki Dima , Ahrar Kamran , Rhines Laurence D. , Gokaslan Ziya L.
Published: May 2009

Object. The current North American experience with minimally invasive vertebro- and kyphoplasty is largely limited to the treatment of benign osteoporotic compression fractures. The objective of this study was to assess the safety and efficacy of these procedures for painful vertebral body (VB) fractures in cancer patients.

Methods. The authors reviewed a consecutive group of cancer patients (21 with myeloma and 35 with other primary malignancies) undergoing vertebro- and kyphoplasty at their institution. Ninety-seven (65 vertebro- and 32 kyphoplasty) procedures were performed in 56 patients during 58 treatment sessions. The mean patient age was 62 years (± 13 years [standard deviation]) and the median duration of symptoms was 3.2 months. All patients suffered intractable spinal pain secondary to VB fractures.

Patients noted marked or complete pain relief after 49 procedures (84%), and no change after five procedures (9%); early postoperative Visual Analog Scale (VAS) pain scores were unavailable in four patients (7%). No patient was worse after treatment. Reductions in VAS pain scores remained significant up to 1 year (p = 0.02, Wilcoxon signed-rank test). Analgesic consumption was reduced at 1 month (p = 0.03, Wilcoxon signed-rank test). Median follow-up length was 4.5 months (range 1 day–19.7 months). Asymptomatic cement leakage occurred during vertebroplasty at six (9.2%) of 65 levels; no cement extravasation was seen during kyphoplasty. There were no deaths or complications related to the procedures. The mean percentage of restored VB height by kyphoplasty was 42 ± 21%.

Conclusions. Percutaneous vertebro- and kyphoplasty provided significant pain relief in a high percentage of patients, and this appeared durable over time. The absence of cement leakage—related complications may reflect the use of 1) high-viscosity cement; 2) kyphoplasty in selected cases; and 3) relatively small 3volume injection. Precise indications for these techniques are evolving; however, they are safe and feasible in well-selected patients with refractory spinal pain due to myeloma bone disease or metastases.
Safety of supplemental endplate screws in thoracic pedicle hook fixation
Authors: Cohen-Gadol Aaron A. , Dekutoski Mark B. , Kim Choll W. , Quast Lynn M. , Krauss William E.
Published: May 2009

Object. The AO Universal Spine System thoracic pedicle hook design includes a fixation screw that passes obliquely through the inferior facet into the pedicle to engage in the posterior portion of the superior vertebral body endplate. This endplate screw provides additional purchase at the hook—bone interface. To determine the safety of this fixation system the authors reviewed the operative notes, radiographs, and outcomes of patients who underwent placement of endplate screws.

Methods. Thirty-six patients (16 male and 20 female patients) who required posterior thoracic instrumentation for spinal deformity (11 cases), neoplasm (15 cases), and traumatic injury (10 cases) were included in this study.

One hundred sixty-four endplate screws were placed (mean 4.3/patient) to augment pedicle hooks for posterior thoracic instrumentation. The number of instrumented levels ranged from seven to 16. The positions of the screws in relation to the pedicle, neural foramen, spinal canal, and endplate were evaluated by assessing plain radiographs and computerized tomography scans (10 cases). Eighty-two screws (56%) were in ideal position. Lateral pedicle wall perforation occurred with 51 screws (35%). Three screws violated the medial wall and nine screws violated the superior or inferior walls of the pedicle. There were no clinical sequelae associated with any of the malpositioned screws. Adequate follow-up radiographic data were not available in five patients. The mean follow-up duration was 19.8 months (range 3–61 months).

Two patients required revision surgery at 3 months and 18 months, respectively, because of hook/endplate screw displacement. There was also one case of an endplate screw fracture without hook displacement that was discovered during subsequent revision surgery. The remainder of the endplate screws and associated pedicles hooks maintained their original positions. There was no case of spinal cord, nerve root, pulmonary, or vascular injury.

Conclusions. The placement of supplemental endplate screws in conjunction with thoracic pedicle hooks can be conducted safely.
Balloon kyphoplasty: one-year outcomes in vertebral body height restoration, chronic pain, and activity levels
Authors: Ledlie Jon T. , Renfro Mark
Published: May 2009

Object. The authors assessed the safety of balloon kyphoplasty in the reduction and repair of osteopenic vertebral compression fractures and report functional outcomes (back pain and activity levels) in the first 96 patients (with 133 fractures) at their institution. Additionally they provide radiographic outcomes in the first 26 patients (41 fractures) treated and followed for 1 year.

Methods. The authors conducted a retrospective chart review of functional outcomes and evaluated radiographs obtained at 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively.

Conclusions. Balloon kyphoplasty safely increases vertebral body height, decreases chronic back pain, and quickly returns geriatric patients to higher activity levels, leading to increased independence and quality of life.
Evaluation of time-dependent spread of tissue damage in experimental spinal cord injury by killed-end evoked potential: effect of high-dose methylprednisolone
Authors: Fukaya Chikashi , Katayama Yoichi , Kasai Masahiko , Kurihara Jun , Maejima Sadahiro , Yamamoto Takamitsu
Published: May 2009

Object. Histopathological studies on spinal cord injury (SCI) have demonstrated time-dependent spread of tissue damage during the initial several hours postinjury. When the long tract within the spinal cord is stimulated, a large monophasic positivity occurs at the injury site. This type of potential, termed the killed-end evoked potential (KEEP), indicates that a nerve impulse approaches but does not pass beyond the injury site. The authors tested the hypothesis that the damage spread can be evaluated as a progressive shift of the KEEP on a real-time basis. The effect of high-dose methylprednisolone sodium succinate (MPSS) on the spread of tissue damage was also examined by this methodology.

Methods. The KEEP was recorded using an electrode array placed on the spinal cord at the T-10 level in cats. This electrode array consisted of multiple 0.2-mm-diameter electrodes, each separated by 0.5 mm. Spinal cord injury was induced using a vascular clip (65 g pinching pressure for 30 seconds). The midline posterior surface of the spinal cord was stimulated bipolarly at the C-7 level by applying a single pulse at supramaximal intensity. During the initial period of 6 hours postinjury, the localization of the largest KEEP shifted progressively up to 2.5 mm rostral from the injury site. The amplitude of the KEEP recorded at the injury site decreased to 55 to 70% and became slightly shortened in latency as the localization of the largest KEEP shifted rostrally. These findings imply that the injury site KEEP represents the volume-conducted potential of the largest KEEP at the site of the conduction block. It moved away from the injury site in association with the damage spread, and this was confirmed histopathologically. A decrease in amplitude of KEEP at the injury site appeared to be the most sensitive measure of the damage spread, because the amplitude of the volume-conducted KEEP is inversely proportional to the square of the distance between the recording site and site of conduction block. Administered immediately after SCI, MPSS clearly inhibited these events, especially within 30 minutes postinjury.

Conclusions. The KEEP enables sequential evaluation to be made of the time-dependent spread of tissue damage in SCI in the same animal. It is, therefore, useful for detecting the effect of therapeutic interventions and for determining the therapeutic time window. The efficiency of MPSS to inhibit the spread of damaged tissue appeared to be maximized when it was administered within the initial 30-minute period postinjury.
Transient rotational compression of the vertebral artery caused by herniated cervical disc
Authors: Nemecek Andrew N. , Newell David W. , Goodkin Robert
Published: May 2009

✓ Of the many causes of vertebrobasilar insufficiency (VBI), extrinsic compression of the vertebral artery (VA) is relatively uncommon. A syndrome of VBI caused by extrinsic compression of the VA secondary to head rotation has been termed positional vertebrobasilar ischemia. The authors present a case of transient VBI caused by herniation of a cervical disc. Transcranial Doppler ultrasonography was used preoperatively to confirm the diagnosis and intraoperatively to monitor cerebral perfusion and to confirm that adequate decompression of the VA had been achieved.
Congenital spondylolysis of the axis with associated myelopathy
Authors: Kubota Motoo , Saeki Naokatsu , Yamaura Akira , Yamamoto Yoshiaki , Nemoto Yuko , Fukutake Toshio
Published: May 2009

✓ Cervical spondylolysis is a rare clinical entity and occurs predominantly at the C-6 level. The authors describe a patient with congenital spondylolysis of the axis that caused myelopathy. The patient was a 57-year-old woman with long-standing gait disturbance. Plain cervical radiography revealed a radiolucent defect across the pedicle of the axis. Magnetic resonance imaging of the cervical spine in the neutral, flexion, and extension neck positions as well as a computerized tomography myelography in the neutral neck position failed to demonstrate any spinal cord compression. When she rotated her neck, however, the spinal cord was caught between the hypertrophic anterior arch of the atlas and posterior part of the slipped pedicle of the axis on the contralateral side. The spinal cord was transformed into a pear shape. Mechanical injury to the spinal cord seemed to explain her neurological presentation. This is, to the authors' knowledge, the 15th case of axial spondylolysis and the sixth case of spinal cord involvement of the cervical spondylolysis. No cases involving myelopathy secondary to such a unique mechanism have been reported previously in the literature.