Clinical and Radiographic Outcomes After Minimally Invasive Transforaminal Lumbar Interbody Fusion-Early Experience Using a Biplanar Expandable Cage for Lumbar Spondylolisthesis.

BACKGROUND: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is a surgical technique frequently used to treat symptomatic lumbar spondylolisthesis. We aim to investigate the safety and efficacy of using a biplanar expandable cage in the treatment of symptomatic lumbar spondylolisthesis using a MIS TLIF approach. METHODS: A retrospective review of patient records was performed on patients who underwent MIS TLIF for symptomatic lumbar spondylolisthesis using the FlareHawk cage over a 12-month period. Patient demographics, as well as preoperative and postoperative clinical and radiographic outcome measures were recorded and analyzed. RESULTS: A total of 13 consecutive patients underwent MIS TLIF for symptomatic spondylolisthesis during the study period. The mean age was 60.2 ± 13.9 years, and 61.5% were female. The mean preoperative and postoperative slippage was 7.0 ± 3.0 mm and 1.0 ± 1.9 mm, respectively. The preoperative mean segmental lordosis was 5.1° ± 6.0°, mean anterior, posterior disc, and foraminal height were 9.1 ± 3.9 mm, 5.7 ± 1.5 mm, and 11.0 ± 2.0 mm, respectively. The postoperative mean segmental lordosis was 6.8° ± 4.7°, and mean anterior, posterior disc, and foraminal height were 11.4 ± 2.2 mm, 7.8 ± 1.0 mm, and 12.3 ± 1.3 mm. There was improvement in all radiographic parameters postoperatively. The mean Visual Analog Scale (VAS) back pain, VAS leg pain improved from 7.0 ± 2.9 and 5.1 ± 3.0 preoperatively to 3.1 ± 2.9 and 1.1 ± 1.7 at the latest clinic follow-up visit, respectively (P = .0081). The mean EuroQol-Five Dimensions (EQ5D) score improved from 0.37 ± 1.7 to 0.66 ± 0.23 after surgery. There was no subsidence, endplate violation, cage migration, or other implant-related complications. No patient required reoperation. CONCLUSIONS: The biplanar expandable cage is both safe and efficacious in treating symptomatic lumbar spondylolisthesis using the MIS TLIF approach. Spine surgeons should be familiar with the biplanar expandable cage technology and keep it in their armamentarium in surgical treatment of lumbar spondylolisthesis. LEVEL OF EVIDENCE: 4.

Cytokines in umbilical cord blood-derived cellular product: a mechanistic insight into bone repair.

AIM: Umbilical cord blood (UCB) finds frequent applications in regenerative medicine. We evaluated the role of cytokines present in a uniquely processed, UCB-derived cellular allograft product (UCBp). MATERIALS & METHODS: Luminex multiplex assay and standard cell biology methods were employed. RESULTS: Study with allografts from 33 donors identified 44 quantifiable cytokines in the UCBp derived conditioned media (CM). The UCBp-CM elevated proliferation and migration rates of mesenchymal stem cells (MSCs) and bone marrow stromal cells. Moreover, UCBp-CM induced secretion of VEGF-A and osteoprotegerin, which promoted angiogenesis of endothelial cells and positively influenced the osteogenic differentiation of MSCs, respectively. CONCLUSION: Cytokines in UCBp stimulate cellular processes important for bone regeneration, making UCBp an excellent candidate for potential applications in orthopedic procedures like bone non-union and spinal fusion.

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF): surgical technique, long-term 4-year prospective outcomes, and complications compared with an open TLIF cohort.

Transforaminal lumbar interbody fusion (TLIF) is an important surgical option for the treatment of back pain and radiculopathy. The minimally invasive TLIF (MI-TLIF) technique is increasingly used to achieve neural element decompression, restoration of segmental alignment and lordosis, and bony fusion. This article reviews the surgical technique, outcomes, and complications in a series of 144 consecutive 1- and 2-level MI-TLIFs in comparison with an institutional control group of 54 open traditional TLIF procedures with a mean of 46 months' follow-up. The evidence base suggests that MI-TLIF can be performed safely with excellent long-term outcomes.

Minimally invasive lateral extracavitary corpectomy: cadaveric evaluation model and report of 3 clinical cases.

OBJECT: In this paper, the authors' goal was to demonstrate the clinical and technical nuances of a minimally invasive lateral extracavitary approach (MI-LECA) for thoracic corpectomy and anterior column reconstruction. METHODS: A cadaveric feasibility study and the subsequent application of this approach in 3 clinical cases are reported. Six procedures were completed in 3 human cadavers. Minimally invasive, extrapleural thoracic corpectomies were performed with the aid of a 24-mm tubular retraction system, using a posterolateral incision and an oblique approach angle. Fluoroscopy and postprocedural CT scanning, using 3D volumetric averaging software, was used to evaluate the degree of bone removal and decompression. Three clinical cases, including a T-11 burst fracture, a T-7 plasmacytoma, and a T4-5 vertebral body (VB) tuberculosis lesion, were treated using the approach. RESULTS: At 6 cadaveric levels, the mean circumferential volumetric decompression was 48% ± 16%, and the mean resection of the VB was 72% ± 13%. The mean change in anterior and posterior vertebral height with expansion of the corpectomy cage was 47 and 61 mm, respectively. There were no violations of the pleura or dura. Pedicle screw reliability was 95.8% (23 of 24 screws) with a single lateral breach. All 3 patients in the clinical cohort had excellent clinical outcomes. There was a single pleural tear requiring chest tube drainage. Operative images and a video clip are provided to illustrate the approach. CONCLUSIONS: A minimally invasive lateral extracavitary thoracic corpectomy has the ability to provided excellent spinal cord decompression and VB resection. The procedure can be completed safely and successfully with minimal blood loss and little associated morbidity. This approach has the potential to improve upon established traditional open corridors for posterolateral thoracic corpectomy.

Somatosensory-evoked potential asymmetry in medullary ischemia during cervical spine surgery.

This report describes how somatosensory-evoked potentials (SEPs) can detect acute medullary ischemia during cervical spine surgery. This article describes how asymmetric SEP intraoperative monitoring changes can localize medullary ischemia. Localization of change was validated by postoperative magnetic resonance imaging (MRI). A 68-year-old man underwent cervical posterior fusion with monitoring of bilateral SEPs of the upper and lower extremities. The SEPs disappeared during initial exposure of the C1 lamina. Changes were asymmetric in degree and duration. Brain MRI postoperatively demonstrated bilateral posterior inferior cerebellar artery (PICA) territory infarcts involving the left lateral medulla. This illustrates how intraoperative SEP monitoring can provide important information on the functional integrity of brainstem structures even during cervical surgery. A knowledge of medullary anatomy and vascular territories is necessary for interpreting SEP changes. In cervical surgery, SEPs incidentally monitor the integrity of the brainstem while monitoring the spinal cord. The asymmetry of SEP change seen here was consistent with medullary level impairment, where the vascular territory is lateralized in contrast to the symmetric anterior spinal artery territory.

Emerging techniques in the minimally invasive treatment and management of thoracic spine tumors.

Over the past decade, the development and refinement of minimally invasive spine surgery techniques has lead to procedures with the potential to minimize iatrogenic and post-operative sequelae that may occur during the surgical treatment of various pathologies. In a similar manner, parallel advances in other current treatment technologies have led to the development of other minimally invasive treatments of spinal malignancies. These advances include percutaneous techniques for vertebral reconstruction, including vertebroplasty and kyphoplasty, the development of safe and effective spinal radiosurgery, and minimal-access spinal surgical procedures that allow surgeons to safely decompress and reconstruct the anterior spinal column. The advent of these new techniques has given modern practitioners treatment options in situations where they previously were limited by the potentially significant morbidities of the available techniques. Here, the authors discuss the application of current minimally invasive technologies in the treatment of malignancies of the thoracic spine, focusing on vertebral kyphoplasty, spinal radiosurgery, and minimally invasive spinal decompression techniques. The author's describe how these emerging treatment options are significantly expanding the options open to clinicians in the treatment of thoracic spinal column malignancies. Specific illustrative case examples are provided. The development of these techniques has the potential to improve clinical outcomes, limit surgical morbidity, and also improve the safety and efficiency of treatment pathways.

A minimally invasive technique for percutaneous lumbar facet augmentation: Technical description of a novel device.

BACKGROUND: We describe a new posterior dynamic stabilizing system that can be used to augment the mechanics of the degenerating lumbar segment. The mechanism of this system differs from other previously described surgical techniques that have been designed to augment lumbar biomechanics. The implant and technique we describe is an extension-limiting one, and it is designed to support and cushion the facet complex. Furthermore, it is inserted through an entirely percutaneous technique. The purpose of this technical note is to demonstrate a novel posterior surgical approach for the treatment of lumbar degenerative. METHODS: This report describes a novel, percutaneously placed, posterior dynamic stabilization system as an alternative option to treat lumbar degenerative disk disease with and without lumbar spinal stenosis. The system does not require a midline soft-tissue dissection, nor subperiosteal dissection, and is a truly minimally invasive means for posterior augmentation of the functional facet complex. This system can be implanted as a stand-alone procedure or in conjunction with decompression procedures. RESULTS: One-year clinical results in nine individual patients, all treated for degenerative disease of the lower lumbar spine, are presented. CONCLUSIONS: This novel technique allows for percutaneous posterior dynamic stabilization of the lumbar facet complex. The use of this procedure may allow a less invasive alternative to traditional approaches to the lumbar spine as well as an alternative to other newly developed posterior dynamic stabilization systems.

Sacral laminoplasty and cystic fenestration in the treatment of symptomatic sacral perineural (Tarlov) cysts: Technical case report.

BACKGROUND: Perineural cysts of the sacrum, or Tarlov cysts, are cerebrospinal fluid (CSF)-filled sacs that commonly occur at the intersection of the dorsal root ganglion and posterior nerve root in the lumbosacral spine. Although often asymptomatic, these cysts have the potential to produce significant symptoms, including pain, weakness, and/or bowel or bladder incontinence. We present a case in which the sacral roof is removed and reconstructed via plated laminoplasty and describe how this technique could be of potential use in maximizing outcomes. METHODS: We describe technical aspects of a sacral laminoplasty in conjunction with cyst fenestration for a symptomatic sacral perineural cyst in a 50-year-old female with severe sacral pain, lumbosacral radiculopathy, and progressive incontinence. This patient had magnetic resonance imaging (MRI) and computed tomography (CT)-myelographic evidence of a non-filling, 1.7 × 1.4 cm perineural cyst that was causing significant compression of the cauda equina and sacral nerve roots. This surgical technique was also employed in a total of 18 patients for symptomatic tarlov cysts with their radiographic and clinical results followed in a prospective fashion. RESULTS: Intraoperative images, drawings, and video are presented to demonstrate both the technical aspects of this technique and the regional anatomy. Postoperative MRI scan demonstrated complete removal of the Tarlov cyst. The patient's symptoms improved dramatically and she regained normal bladder function. There was no evidence of radiographic recurrence at 12 months. At an average 16 month followup interval 10/18 patients had significant relief with mild or no residual complaints, 3/18 reported relief but had persistent coccydynia around the surgical area, 2/18 had primary relief but developed new low back pain and/or lumbar radiculopathy, 2/18 remained at their preoperative level of symptoms, and 1/18 had relief of their preoperative leg pain but developed new pain and neurological deficits. CONCLUSIONS: Sacral laminoplasty and microscopic cystic fenestration is a feasible approach in the operative treatment of this difficult, and often controversial, spinal pathology. This technique may be used further and studied in an attempt to minimize potential surgical morbidity, including CSF leaks, cyst recurrence, and sacral insufficiency fractures.

Ossification of the posterior longitudinal ligament: pathogenesis, management, and current surgical approaches. A review.

Ossification of the posterior longitudinal ligament (OPLL) is an important cause of cervical myelopathy that results from bony ossification of the cervical or thoracic posterior longitudinal ligament (PLL). It has been estimated that nearly 25% of patients with cervical myelopathy will have features of OPLL. Patients commonly present in their mid-40s or 50s with clinical evidence of myelopathy. On MR and CT imaging, this can be seen as areas of ossification that commonly coalesce behind the cervical vertebral bodies, leading to direct ventral compression of the cord. While MR imaging will commonly demonstrate associated changes in the soft tissue, CT scanning will better define areas of ossification. This can also provide the clinician with evidence of possible dural ossification. The surgical management of OPLL remains a challenge to spine surgeons. Surgical alternatives include anterior, posterior, or circumferential decompression and/or stabilization. Anterior cervical stabilization options include cervical corpectomy or multilevel anterior cervical corpectomy and fusion, while posterior stabilization approaches include instrumented or noninstrumented fusion or laminoplasty. Each of these approaches has distinct advantages and disadvantages. While anterior approaches may provide more direct decompression and best improve myelopathy scores, there is soft-tissue morbidity associated with the anterior approach. Posterior approaches, including laminectomy and fusion and laminoplasty, may be well tolerated in older patients. However, there often is associated axial neck pain and less improvement in myelopathy scores. In this review, the authors discuss the epidemiology, imaging findings, and clinical presentation of OPLL. The authors additionally discuss the merits of the different surgical techniques in the management of this challenging disease.

Minimally invasive extracavitary approach for thoracic discectomy and interbody fusion: 1-year clinical and radiographic outcomes in 13 patients compared with a cohort of traditional anterior transthoracic approaches.

OBJECT: Open transthoracic approaches, considered the standard in treating thoracic disc herniation (TDH), are associated with significant comorbidities. The authors describe a minimally invasive lateral extracavitary tubular approach for discectomy and fusion (MIECTDF) to treat TDH. METHODS: In 13 patients (5 men, 8 women; mean age 51.8 years) with myelopathy and 15 noncalcified TDHs, the authors achieved a far-lateral trajectory by dilating percutaneously to a 20-mm working portal docked at the transverse process-facet junction, which then provided a corridor for a near-total discectomy, bilateral laminotomies, and interbody arthrodesis requiring minimal cord retraction. A cohort of 11 demographically comparable patients treated via transthoracic approaches was used as control. RESULTS: Preoperative Frankel grades were B in 1 patient, C in 4, D in 5, and E in 3, whereas at mean of 10 months, 11 had Grade E function and 2 had Grade D function. Mean surgical metrics were operating room time 93.75 minutes, blood loss 33 ml, and hospital stay 3.1 days. Complications included 4 transient paresthesias, 1 CSF leak, 1 abdominal wall weakness, and 3 nonwound infections. One-year follow-up MR imaging revealed full decompression in all cases and no cage migration. Mean visual analog scales scores preoperative, at 6 weeks, 3 months, and 1 year were 5.6, 4.5, 3.2, and 1.2, respectively. No differences existed in preoperative clinical and radiographic profile of the study and control groups. Compared with controls, the MIECTDF group achieved superior scores in all metrics (p < 0.01) except for equivalent 1-year neurological outcomes. CONCLUSIONS: Compared with transthoracic procedures, MIECTDF effectively decompressed the spinal canal, yielding identical 1-year radiographic and clinical outcomes to those seen in controls, while producing superior clinical scores in the interim. Thus, MIECTDF is the authors' treatment of choice for TDH.

Minimally invasive percutaneous transpedicular screw fixation: increased accuracy and reduced radiation exposure by means of a novel electromagnetic navigation system.

BACKGROUND: Minimally invasive percutaneous pedicle screw instrumentation methods may increase the need for intraoperative fluoroscopy, resulting in excessive radiation exposure for the patient, surgeon, and support staff. Electromagnetic field (EMF)-based navigation may aid more accurate placement of percutaneous pedicle screws while reducing fluoroscopic exposure. We compared the accuracy, time of insertion, and radiation exposure of EMF with traditional fluoroscopic percutaneous pedicle screw placement. METHODS: Minimally invasive pedicle screw placement in T8 to S1 pedicles of eight fresh-frozen human cadaveric torsos was guided with EMF or standard fluoroscopy. Set-up, insertion, and fluoroscopic times and radiation exposure and accuracy (measured with post-procedural computed tomography) were analyzed in each group. RESULTS: Sixty-two pedicle screws were placed under fluoroscopic guidance and 60 under EMF guidance. Ideal trajectories were achieved more frequently with EMF over all segments (62.7% vs. 40%; p = 0.01). Greatest EMF accuracy was achieved in the lumbar spine, with significant improvements in both ideal trajectory and reduction of pedicle breaches over fluoroscopically guided placement (64.9% vs. 40%, p = 0.03, and 16.2% vs. 42.5%, p = 0.01, respectively). Fluoroscopy time was reduced 77% with the use of EMF (22 s vs. 5 s per level; p < 0.0001) over all spinal segments. Radiation exposure at the hand and body was reduced 60% (p = 0.058) and 32% (p = 0.073), respectively. Time for insertion did not vary between the two techniques. CONCLUSIONS: Minimally invasive pedicle screw placement with the aid of EMF image guidance reduces fluoroscopy time and increases placement accuracy when compared with traditional fluoroscopic guidance while adding no additional time to the procedure.

Anatomical considerations for subaxial (C2) pedicle screw placement: a radiographic study with computed tomography in 93 patients.

STUDY DESIGN: Radiographic study. OBJECTIVE: More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial computed tomography. BACKGROUND DATA: Although earlier studies have analyzed the anatomy of the C2 pars interarticularis, little attention has been focused on the dimensions of the C2 pedicle. METHODS: Ninety-three patients (47 males, 46 females; mean age 48.4 y) who had previous cervical spinal computed tomography imaging were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, ie, the angle between the pedicle axis and the midline of the vertebral body). RESULTS: The overall mean pedicle width was 5.8+/-1.2 mm. The mean pedicle width in male patients (6.0+/-1.3 mm) was greater than that in the female patients (5.6+/-1.1 mm). This difference was not found to be statistically significant (P=0.679). The overall mean PTA was 43.9+/-3.9 degrees. The mean PTA in male patients was 43.2+/-3.8 degrees, whereas that in female patients was 44.7+/-3.7 degrees. CONCLUSIONS: Given the significant variability in pedicle widths and the need for precise trajectory planning in pedicle cannulation, preoperative planning is absolutely mandatory. A significant percentage of patients have pedicle widths that may not accommodate screw fixation. In addition, the angle of entry into the C2 pedicle must be carefully measured for safe instrumentation at this level.

Primary bony non-Hodgkin lymphoma of the cervical spine: a case report.

INTRODUCTION: Non-Hodgkin lymphoma primarily originating from the bone is exceedingly rare. To our knowledge, this is the first report of primary bone lymphoma presenting with progressive cord compression from an origin in the cervical spine. Herein, we discuss the unusual location in this case, the presenting symptoms, and the management of this disease. CASE PRESENTATION: We report on a 23-year-old Caucasian-American man who presented with two months of night sweats, fatigue, parasthesias, and progressive weakness that had progressed to near quadriplegia. Magnetic resonance (MR) imaging demonstrated significant cord compression seen primarily at C7. Surgical management, with corpectomy and dorsal segmental fusion, in combination with adjuvant chemotherapy and radiation therapy, halted the progression of the primary disease and preserved neurological function. Histological analysis demonstrated an aggressive anaplastic large cell lymphoma. CONCLUSION: Isolated primary bony lymphoma of the spine is exceedingly rare. As in our case, the initial symptoms may be the result of progressive cervical cord compression. Anterior corpectomy with posterolateral decompression and fusion succeeded in preventing progressive neurologic decline and maintaining quality of life. The reader should be aware of the unique presentation of this disease and that surgical management is a successful treatment strategy.

Combined anterior C2-C3 fusion and C2 pedicle screw fixation for the treatment of unstable hangman's fracture: a contrast to anterior approach only.

STUDY DESIGN: A retrospective clinical study was used to evaluate the effect of a new surgical treatment of the hangman's fractures. OBJECTIVE: To determine the treatment efficacy of combined anterior C2-C3 reduction and fusion and posterior compressive C2 pedicle screw fixation for the management of unstable hangman's fractures. SUMMARY OF BACKGROUND DATA: The classification of hangman's fractures as proposed by Levine-Edwards was used to classify and guide the treatment of these injuries. Most of these fractures respond to a variety of conservative therapies, but recently, earlier surgery has been increasingly advocated by authors from several countries for the rapid stabilization of these fractures. If surgery is indicated, an anterior approach using a C2-C3 reduction and fusion is preferred usually. Another well-accepted surgical method is the direct transpedicular osteosynthesis by the dorsal approach. However, there was rare report of the combined use of these 2 techniques. METHODS: A group of 45 surgical patients were all diagnosed with radiograph, magnetic resonance imaging (MRI), and 3D CT scans. Initial and final radiographs were measured for anterior translation and angulation of the C2-C3 complex. Initial external skull traction with extension was used in all patients after admission to reduce the fracture. Then an anterior C2-C3 discectomy followed by an interbody fusion and locking plate fixation was performed. Intraoperative reduction was confirmed by fluoroscopic control. About 29 patients therefore received anterior surgeries only since satisfactory reduction was achieved during the procedure. For the 16 patients who had persistent large residual gaps after the anterior procedure, additional same stage posterior C2 compressive pedicle screws were placed. Clinical and radiologic comparisons were performed in these 2 groups. RESULTS: The follow-up ranged from 24 to 54 months, with an average 33.6 months. There was radiographic evidence of continuity of the fracture and the bone graft seen at 4.7 months on average. Neck pain and neurologic deficits resolved in nearly all patients after surgery. The anterior translation of anterior-posterior surgery group decreased more significant compared to anterior surgery group, although with no statistical significance. The fractures were closed with a slight gap no more than 2 mm in anterior-posterior surgery group. The residual kyphosis in anterior-posterior surgery group was still a little larger than it in anterior surgery group. No internal fixation failures or infections were observed. CONCLUSION: We believe that the need for single stage 360° fusion of hangman's fractures can be somewhat predicted by a combination of high resolution imaging. For hangman's fractures with significant deformity and gapping, it is our experience that immediate single-stage anterior-posterior reduction, instrumentation, and arthrodesis achieve superior postoperative reduction and long-term functional outcomes.

A Comparison of fixed-hole and slotted-hole dynamic plates for anterior cervical discectomy and fusion.

STUDY DESIGN: A retrospective review of clinical data at 1 institution was performed. OBJECTIVES: To compare the clinical and radiologic outcomes between fixed-hole and slotted-hole dynamic cervical plates. SUMMARY OF BACKGROUND DATA: Anterior cervical plating is commonly used to increase stability and promote spinal fusion. Two techniques, fixed-hole dynamic plating that uses variable angled screws and slotted-hole dynamic plating that permits sliding, are viable options, but there have been no clinical studies comparing their effectiveness. METHODS: Fifty-six patients at 1 institution having anterior cervical discectomy and fusion for degenerative disease over a 5-year period were entered into this study. Surgeries were performed with 1 of the dynamic plates for 1 to 3 levels. For the slotted-hole dynamic plate group, a slotted-hole plate was used (ABC, Aesculap, Tuttlingen, Germany or C-tek, Biomet, Parssipany, NJ) and for the fixed-hole dynamic plated group, a variable angled screw was used (C-tek, Biomet, Parssipany, NJ). Radiographic measurements included were graft subsidence, lordotic angle change from each end plate of fusion construct, and implant translation from end plates after a minimum of 12 months follow-up. Fusion state and clinical outcome using Odom's criteria were also evaluated. RESULTS: Demographics were not different among patient populations. The average age of the patients was 51.0 years (range: 27 to 77 y). Mean follow-up period was 20.6 months (range: 12 to 41 mo). Slotted-hole dynamic plates were used for 29 patients (ABC plate, 17; C-tek plate, 12) and fixed-hole dynamic plates for 27 patients. Clinical outcomes and pseudoarthrosis rates were similar for both types of plates. Radiographic measurements showed a statistically significant increased incidence of graft subsidence and implant translation with the slotted-hole dynamic plates. Loss of lordosis was also greater in the slotted-hole dynamic plated group, although the difference was not statistically significant. CONCLUSIONS: The use of a fixed-hole dynamic plate is more favorable in regards to graft subsidence and implant translation in the follow-up period, although clinical outcome and fusion rates are similar in patients with either the fixed-hole or slotted-hole dynamic plates.

Symptomatic ectopic bone formation after off-label use of recombinant human bone morphogenetic protein-2 in transforaminal lumbar interbody fusion.

OBJECT: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been approved for use in the lumbar spine in conjunction with the lumbar tapered cage. However, off-label use of this osteoinductive agent is observed with anterior fusion applications as well as with both posterior lumbar interbody fusion and transforaminal lumbar interbody fusion (TLIF). Complications using rhBMP-2 in the cervical spine have been reported. Although radiographic evidence of ectopic bone in the lumbar spine has been described following rhBMP-2 use, this finding was not previously believed to be of clinical relevance. METHODS: This study was a retrospective review of 4 patients who underwent minimally invasive spinal TLIF (MIS-TLIF) in which bone fusion was augmented with rhBMP-2 applied to an absorbable collagen sponge. Case presentations, operative findings, imaging data, and follow-up findings were reviewed. RESULTS: Four cases with delayed symptomatic neural compression following the off-label use of rhBMP-2 with MIS-TLIF were identified. CONCLUSIONS: Although previously believed to be only a radiographic finding, the development of ectopic bone following rhBMP-2 use in lumbar fusion can be clinically significant. This paper describes 4 cases of delayed neural compression following MIS-TLIF. The reader should be aware of this potential complication following the off-label use of rhBMP-2 in the lumbar spine.

An intensive, progressive exercise program reduces disability and improves functional performance in patients after single-level lumbar microdiskectomy.

BACKGROUND: Restoration of physical function following lumbar microdiskectomy may be influenced by the postoperative care provided. OBJECTIVE: The purpose of this study was to examine the effectiveness of a new interventional protocol to improve functional performance in patients who have undergone a single-level lumbar microdiskectomy. SETTING: The study was conducted in physical therapy outpatient clinics. DESIGN AND PARTICIPANTS: Ninety-eight participants (53 male, 45 female) who had undergone a single-level lumbar microdiskectomy were randomly allocated to receive education only or exercise and education. INTERVENTION AND MEASUREMENTS: The exercise intervention consisted of a 12-week periodized program of back extensor strength (force-generating capacity) and endurance training and mat and upright therapeutic exercises. The Oswestry Disability Index (ODI) and physical measures of functional performance were tested 4 to 6 weeks postsurgery and 12 weeks later, following completion of the intervention program. Because some participants sought physical therapy outside of the study, postintervention scores were analyzed for both an as-randomized (2-group) design and an as-treated (3-group) design. RESULTS: In the 2-group analyses, exercise and education resulted in a greater reduction in ODI scores and a greater improvement in distance walked. In the 3-group analyses, post hoc comparisons showed a significantly greater reduction in ODI scores following exercise and education compared with the education-only and usual physical therapy groups. LIMITATIONS: The limitations of this study include a lack of adherence to group assignment, disproportionate therapist contact time among treatment groups, and multiple use of univariate analyses. CONCLUSIONS: An intensive, progressive exercise program combined with education reduces disability and improves function in patients who have undergone a single-level lumbar microdiskectomy.

Anatomical considerations for cervical pedicle screw insertion: the use of multiplanar computerized tomography measurements in 122 consecutive clinical cases.

BACKGROUND CONTEXT: Successful placement of pedicle screws in the cervical spine requires a sufficient three-dimensional understanding of pedicle morphology to allow accurate identification of the screw axis. PURPOSE: The goal of the present study was to assess morphologic trends from one level to the next with respect to linear and angular parameters associated with the subaxial cervical pedicles. STUDY DESIGN/SETTING: We evaluated the pedicle morphology of cervical spine using axial and sagittal computed tomography (CT) imaging. The C3-C7 vertebrae in 122 patients (610 vertebrae) were evaluated (age range, 14-93; mean, 48 years). METHODS: Thin cut (2.5mm thickness) axial CT images were measured. Sagittal reconstructions were obtained using 1.25-mm thickness slices. The following pedicle parameters were assessed: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis), pedicle height (PH, rostro-caudal dimension of the pedicle determined on the sagittal image), maximal screw length (MSL, distance from the posterior cortex of the lateral mass to the anterior wall of the vertebral body along the pedicle axis), and pedicle transverse angle (PTA, angle between the pedicle axis and the midline vertebral body). RESULTS: The overall mean PW and PH ranged from 4.7 to 6.5mm and 6.4 to 7.0mm, respectively. For both these parameters there was a trend toward increasing size proceeding caudally in the cervical spine. The mean PW and PH was greater in males than in females, and this difference was statistically significant at all levels (p<.0001). The overall mean MSL ranged from 29.9 to 32.9 mm. All intersections of the pedicle axis and the posterior cortex of the lateral mass were located at the most lateral portion of the lateral mass for the C3-C6 vertebrae. The overall mean PTA ranged from 37.8 degrees to 45.3 degrees . The overall mean PTA was approximately 44 degrees from C3 to C6 and 37.8 degrees at C7. CONCLUSION: The findings of our radiological anatomical study suggest that the preoperative CT scans of patients undergoing cervical transpedicular fixation should be thoroughly analyzed and close attention paid to the pedicle size and its angulation. The placement of cervical pedicle screws should be individualized for each patient and based on detailed preoperative planning.

Considerações anatômicas sobre a localização dos parafusos pediculares em C2: utilização das medidas da tomografia computadorizada / Consideraciones anatómicas de la cocalización de los tornillos pediculares en C2: uitlización de las medidas de la tomografia computadorizada / Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements

More detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial CT. METHODS: ninety three patients (47 males, 46 females mean age 48 years) who had cervical spinal CT imaging performed were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle width (PW, the mediolateral diameter of the pedicle isthmus, perpendicular to the pedicle axis) and pedicle transverse angle (PTA, that is, the angle between the pedicle axis and the midline of the vertebral body). RESULTS: the overall mean pedicle width was 5.8 1.2mm. The mean pedicle width in males (6.01.3mm) was greater than that in the female subjects (5.6 1.1mm). This difference was not found to be statistically significant (p=.6790). The overall mean pedicle transverse angle was 43.93.9 degrees. The mean PTA in males was 43.23.8 degrees, while that in females was 44.73.7 degrees. CONCLUSION: preoperative planning is absolutely mandatory, particularly in determining not only screw trajectory, but in analyzing individual patient anatomy and reception to a C2 pedicle screw.

O conhecimento detalhado das características anatômicas do pedículo de C2 é necessário para minimizar os riscos relacionados com a colocação dos parafusos. O objetivo deste trabalho é avaliar as medidas lineares e angulares do eixo axial verdadeiro do pedículo de C2 utilizando tomografia computadorizada. MÉTODOS: foram utilizadas tomografias computadorizadas axiais de 93 pacientes (47 do sexo masculino e 46 do sexo feminino) com média de idade de 48 anos. As imagens axiais do pedículo de C2 foram selecionadas para o estudo e os parâmetros estudados foram: largura do pedículo (diâmetro mediolateral do istmo do pedículo perpendicular ao eixo do pedículo) e o ângulo tranverso do pedículo (ângulo entre o eixo do pedículo e a linha média do corpo vertebral). RESULTADOS: o valor médio da largura do pedículo foi 5,81,2mm. Nos pacientes de sexo masculino o valor médio da largura do pedículo (6,01,3mm) foi maior que nos pacientes de sexo feminino (5,61,1mm). No entanto, não foi observada diferença estatística. O valor médio do ângulo transverso do pedículo foi de 43,93,9 graus, sendo de 43,23,8 graus no sexo masculino e 44,73,7 graus no sexo feminino. CONCLUSÃO: o planejamento e a determinação no período pré-operatório das dimensões anatômicas do pedículo de C2 são importantes para a determinação da trajetória e dimensões do local onde o implante será colocado.

El conocimiento detallado de las características anatómicas del pedículo de C2 es necesario para minimizar los riesgos relacionados con la colocación de los tornillos. El objetivo del estudio fue evaluar las medidas lineares y angulares del eje axial verdadero del pedículo de C2 utilizando la tomografía computadorizada. MÉTODOS: fueron utilizadas tomografías computadorizadas axiales de 93 pacientes (47 del sexo masculino y 46 del sexo femenino) con promedio de edad de 48 años. Las imágenes axiales del pedículo de C2 fueron seleccionadas para el estudio y los parámetros estudiados fueron: Ancho del pedículo (diámetro mediolateral del istmo del pedículo perpendicular al eje del pedículo) y el ángulo transverso del pedículo (ángulo entre el eje del pedículo y la línea media del cuerpo vertebral). RESULTADOS: el valor promedio del ancho pedicular fue de 5.8 1.2mm. En el sexo masculino el valor promedio del ancho del pedículo (6.0 1.3mm) fue mayor comparado con el sexo femenino (5.6 1.1mm), sin embargo no fue observada una diferencia estadística. El valor promedio del ángulo transverso del pedículo fue de 43.9 3.9 grados, siendo de 43.2 3.8 grados en el sexo masculino y 44.7 3.7 grados en el sexo femenino. CONCLUSIÓN: la proyección y determinación en el periodo preoperatorio de las dimensiones anatómicas del pedículo C2 son importantes para la determinación de la trayectoria y dimensiones del local donde el implante será colocado.

Um novo dispositivo percutâneo minimamente invasivo de aumento facetário para o tratamento da radiculopatia lombar e dor axial lombar: descrição técnica, técnica cirúrgica e apresentação de casos / Un nuevo dispositivo percutáneo mínimamente invasivo de aumento facetáreo para el tratamiento de radiculopatía lumbar y dolor axial lumbar: descripción técnica, técnica quirúrgica y presentación de casos / A novel minimally invasive percutaneous facet augmentation device for the treatment of lumbar radiculopathy and axial back pain: technical description, surgical technique and case presentations

To describe a new posterior minimally invasive method of facet stabilization for treatment of the degenerating lumbar motion segment. The biomechanics of this Percudyn (Interventional Spine; Irvine, CA) system are distinct from that of other interspinous dynamic stabilization systems as it acts bilaterally directly within the middle column of the spine. Based on biomechanical evalution, the paired prosthesis supports, cushions, and reinforces the facet complexes by limiting both extension and lateral bending thereby maintaining central and foraminal volumes. METHODS: the Percudyn device consists of a pedicle anchor upon which sits a cushioning polycarbonate-urethane stabilizer that serves as a mechanically reinforcing stop between the inferior and superior articular facets. A 1.5 cm skin incision is made bilaterally over the lower pedicle of the treated segment through which a Jamshidi needle is percutaneously targeted under biplanar fluoroscopic guidance into the caudal aspect of the superior articular process directly underneath the lip of the inferior facet from the level above. Progressive onestep tubular dilation is then performed to secure a small disposable working portal. Through this access, the Percudyn stabilizers are then placed over the wire and anchored bilaterally into the inferior pedicles of the degenerated motion segment. RESULTS: three patients (ages 26-41, male) with significant low back pain as well as radiculopathy with lateral recess stenosis from a large disc herniation/ ligamentum and facet hypertrophy (L4-5 and/or L5-S1) underwent a minimally invasive decompression/ discectomy and bilateral Percudyn placement at each disease level. Each patient had significant relief of both his radiculopathy and axial back pain post-operatively and was discharged home within 18 hours without sequelae. CONCLUSION: this novel technique of percutaneous posterior facet augmentation allows for safe placement of bilateral...

Descrever um método de estabilização facetária posterior minimamente invasivo para tratamento de segmento móvel degenerativo. A biomecânica do sistema Percudyn (Interventional Spine, Irvine, Califórnia) é distinta de outros sistemas de estabilização dinâmica inter-espinhosa, pois este atua direta e bilateralmente dentro da coluna média da coluna vertebral. Baseada em avaliações biomecânicas, a prótese dupla dá suporte, atua como amortecedor e reforça os complexos facetários limitando a extensão e a inclinação lateral, mantendo assim os volumes centrais e foraminais. MÉTODOS: o sistema Percudyn consiste de uma ancora pedicular sobre a qual está apoiado um estabilizador de plicarbonato-uretano que atua como um bloqueio mecanicamente reforçado entre as facetas inferiores e superiores. Uma incisão na pele de 1,5cm é feita bilateralmente sobre o pedículo inferior do segmento a ser tratado, por meio da qual é introduzida percutaneamente uma agulha de Jamshidi com auxílio de fluoroscopia biplanar em direção da porção caudal do processo articular superior, diretamente abaixo da borda da faceta inferior do nível superior. É feita uma dilatação tubular progressiva para assegurar um pequeno e temporário portal de trabalho. Por meio desse acesso, os estabilizadores Percudyn são colocados sobre o fio e ancorados bilateralmente nos pedículos inferiores de cada segmento móvel degenerativo. RESULTADOS: três pacientes (idade de 26 a 41 anos, sexo masculino) com lombalgia significativa, assim como radiculopatia e estenose do recesso lateral em consequência de um grande fragmento de disco herniado, ou hipertrofia ligamentar e facetária (L4-5 e/ou L5-S1) foram submetidos a uma descompressão/discectomia minimamente invasiva e implantação do Percudyn bilateralmente em cada segmento afetado. Todos os pacientes tiveram um alivio pós-operatório significante, tanto da radiculopatia como da dor axial lombar, e alta hospitalar até 18 horas sem sequelas...

Describir un método de estabilización facetárea posterior mínimamente invasiva para tratamiento del segmento móvil degenerativo. La biomecánica del sitema Percudyn (Interventional Spine, Irvine, California) es distinta de otros sistemas de estabilización dinámica interespinosa, pues ésta actúa directamente y bilateralmente dentro de la columna media de la columna vertebral. Con base en evaluaciones biomecánicas, la prótesis dupla da soporte, actúa como amortiguador y refuerza los complejos facetáreos limitando la extensión y la inclinación lateral, manteniendo así los volúmenes centrales y foraminales. MÉTODOS: el sistema Percudyn consiste de un áncora pedicular sobre la cual está apoyado un estabilizador de policarbonato-uretano, que actúa como un bloqueo mecánicamente reforzado entre las facetas inferiores y superiores. Una incisión en la piel de 1.5 cm es hecha bilateralmente sobre el pedículo inferior del segmento a ser tratado, a través del cual es introducida percutáneamente una aguja de Jamshidi con auxilio de fluoroscopia biplanar en dirección a la porción caudal del proceso articular superior, directamente abajo del borde de la faceta inferior del nivel superior. Es hecha una dilatación tubular progresiva para sujetar un pequeño y temporal portal de trabajo. A través de este acceso, los estabilizadores Percudyn son puestos sobre el hilo o alambre y ancorados bilateralmente en los pedículos inferiores de cada segmento móvil degenerativo. RESULTADOS: tres pacientes (edad de 26 a 41 años, sexo masculino) con lumbalgia significativa, así como radiculopatía y estenosis del receso lateral en consecuencia de un fragmento grande del disco herniado, o hipertrofia ligamentar y facetárea (L4-5 y/o L5-S1) fueron sometidos a una descompresión/ disectomía mínimamente invasiva e implantación del Percudyn bilateralmente en cada segmento afectado. Todos los pacientes tuvieron un alivio postoperatorio significativo tanto de la radiculopatía...