Thoracolumbar Vertebral Column Resection With Rectangular Endplate Cages Through a Posterior Approach: Surgical Techniques and Early Postoperative Outcomes.

BACKGROUND: Thoracolumbar pathology can result in compression of neural elements, instability, and deformity. Circumferential decompression with anterior column reconstruction is often required to restore biomechanical stability and minimize the risk of implant failure. OBJECTIVE: To assess the safety and viability of wide-footprint rectangular cages for vertebral column resection (VCR). METHODS: We performed VCR with wide-footprint rectangular endplate cages, which were designed for transthoracic or retroperitoneal approaches. We present our technique using a single-stage posterior approach. RESULTS: A total of 45 patients underwent VCR with rectangular endplate cages. Mean age was 58 yr. Diagnoses included 23 tumors (51%), 14 infections (31%), and 8 deformities (18%). VCRs were performed in 10 upper thoracic, 17 middle thoracic, 14 lower thoracic, and 4 lumbar levels. Twenty-four cases involved a single level VCR (53%) with 18 two-level (40%) and 3 three-level (7%) VCRs. Average procedure duration was 264 min with mean estimated blood loss of 1900 ml. Neurological outcomes were stable in 27 cases (60%), improved in 16 (36%), and worse in 2 (4%). There were 7 medical and 7 surgical complications in 11 patients. There were significant decreases in postoperative thoracic kyphosis (47° vs 35°, P = .022) and regional kyphosis (34° vs 10°, P < .001). There were 2 cases of cage subsidence due to intraoperative endplate violation, neither of which progressed on CT scan at 14 and 35 mo. CONCLUSION: Posterior VCR with rectangular footprint cages is safe and feasible. This provides improved biomechanical stability without the morbidity of a lateral transthoracic or retroperitoneal approach.

Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

Management of aortic injury during minimally invasive lateral lumbar interbody fusion.

PURPOSE: Minimally invasive lateral approaches to the lumbar spine allow for interbody fusion with good visualization of the disk space, minimal blood loss, and decreased length of stay. Major neurologic, vascular, and visceral complications are rare with this approach; however, the steps in management for severe vascular injuries are not well defined. We present a case report of aortic injury during lateral interbody fusion and discuss the use of endovascular repair. METHODS: This study is a case report of an intraoperative aortic injury. RESULTS: A 59-year-old male with ankylosing spondylitis suffered an acute L1 Chance fracture after mechanical fall. He was taken to the operating room for a T10-L4 posterior instrumented fusion followed by a minimally invasive L1-L2 lateral interbody fusion for anterior column support. During the discectomy, brisk arterial bleeding was encountered due to an aortic injury. The vascular surgery team expanded the incision in an attempt to control the bleeding but with limited success. The patient underwent intraoperative angiogram with placement of stent grafts at the level of the injury followed by completion of the interbody fusion. Despite the potentially catastrophic nature of this injury, the patient made a good recovery and was discharged home in stable condition with no new neurologic deficits. CONCLUSIONS: This case highlights the importance of immediate recognition and imaging of any potential vascular injury during minimally invasive lateral interbody fusion. Given the poor outcomes associated with attempted open repair, endovascular techniques provide a valuable tool for the treatment of these complex injuries with significantly less morbidity.

Radiation exposure with hybrid image-guidance-based minimally invasive transforaminal lumbar interbody fusion.

The transforaminal lumbar interbody fusion (TLIF) is used for the treatment of back and leg pain secondary to spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) is associated with less estimated blood loss (EBL), decreased length of stay, lower infection rates, and similar outcomes compared to the traditional TLIF. Fluoroscopy time has been reported with MIS-TLIF, but there are limited data on specific radiation dosages. We performed a retrospective analysis of a prospectively acquired cohort of patients undergoing MIS-TLIF. A total of 50 patients were included. Mean age was 53 years with 60% women and mean BMI of 30 (range 21-41). Diagnoses were as follows: 45 stenosis (90%), 29 spondylolisthesis (58%), 5 facet cysts (10%), 3 scoliosis (6%), and 1 cauda equina syndrome (2%). A single level was fused in 33 cases (66%), two levels in 15 (30%), three levels in 2 (4%). Average cage height was 10 mm with mean EBL of 80 ml and operative time of 240 min. The average radiation doses from intraoperative CT scan and fluoroscopy were 35.3 and 26.5 mGy, respectively. Average CT scan and fluoroscopy times were 5.2 and 37.1 s, respectively, for a total of 42.2 s. Average length of stay was 3 days (range 1-7 days). Although these data represent a preliminary experience, by streamlining the timing of intraoperative CT scan and minimizing the amount of intraoperative fluoroscopy, this protocol has the potential for decreasing operative time and radiation exposure.

Adult Spinal Deformity Correction with Multi-level Anterior Column Releases: Description of a New Surgical Technique and Literature Review.

STUDY DESIGN: Case series. OBJECTIVE: To evaluate radiographic and clinical outcomes of adults with spinal deformity treated with multilevel anterior column releases (ACR). SUMMARY OF BACKGROUND DATA: Pedicle subtraction osteotomy can be used effectively to correct spinal deformity; however, it is not without complications. ACR is an attractive alternative minimally invasive technique for spinal deformity correction, although few clinical reports on its clinical effectiveness exist. METHODS: Adults with spinal deformity who underwent multilevel ACRs (≥2) followed by open posterior instrumentation with a minimum 1-year follow-up were retrospectively reviewed. Deformity radiographic data and clinical outcomes, including the Oswestry Disability Index (ODI) and the EuroQol-5D were analyzed. RESULTS: Eight patients [7 female, 1 male; mean age 65 y (49-79 y)] met inclusion criteria. The mean follow-up was 18.4 months (12-28 mo). The average number of levels treated with an ACR per patient was 2.4 (2-3). There were no anterior approach-related complications. The average number of levels instrumented posteriorly was 8.1 (3-15). Six patients underwent Schwab type 1 posterior osteotomies (partial facetectomies). After the first anterior stage, there was a significant increase in the lumbar lordosis and significant decreases in the sagittal vertical axis, pelvic tilt, and lumbopelvic mismatch (P<0.05). After the second stage there was no significant change in the sagittal vertical axis, lumbar lordosis, pelvic tilt, or lumbopelvic mismatch relative to the values obtained after ACR. There was significantly less disability postoperatively [ODI: 15 (0-30)] compared with preoperatively [ODI: 46 (16-80)] (P<0.01). There was significant improvement in general health after operation, as assessed by the EuroQol-5D utility scores [preop: 0.44 (0.21-0.82) vs. postop: 0.71 (0.60-0.80)] (P=0.01). Back and leg visual analog scale pain scores improved significantly postoperatively. CONCLUSIONS: A staged approach using multilevel ACRs with open posterior instrumentation has an acceptable complication profile and provides excellent restoration of sagittal and coronal balance and pelvic parameters in adults with spinal deformity.

Multilevel Corpectomy With Anterior Column Reconstruction and Plating for Subaxial Cervical Osteomyelitis.

STUDY DESIGN: A retrospective case series. OBJECTIVE: The aim of this study was to evaluate patients with cervical spine osteomyelitis who underwent multilevel (≥2) subaxial corpectomies and anterior column reconstruction and plating. SUMMARY OF BACKGROUND DATA: Neglected multilevel subaxial cervical osteomyelitis is a potentially dangerous disease. As it is rare, early radiographic and clinical outcomes after multilevel anterior corpectomy and reconstruction for subaxial cervical osteomyelitis are incompletely defined. METHODS: Adults who underwent multilevel corpectomy and anterior plating/reconstruction for subaxial cervical osteomyelitis at two institutions were reviewed. Analysis of patient demographics, operative details, and radiographic cervical alignment parameters [segmental kyphosis, cervical lordosis, C2-7 sagittal vertical axis (SVA)] was performed. RESULTS: Nineteen patients [15 males, four females; average age 48 years (20-81 yrs)] met inclusion criteria. The majority had pre-operative neurologic deficits or was immunosuppressed. All were treated with ≥6 weeks of intravenous antibiotics following operation. All had anterior plating/reconstruction with titanium cages (expandable-6; mesh-6) or structural bone graft (fibular allogaft-6; tricortical iliac crest-1). The average number of corpectomies was 2.4 (2-4). The average numbers of levels fused anteriorly was 4.4 (4-6) and posteriorly was 6.3 (4-9). The majority of patients (74%) was treated with an anterior/posterior approach. Average follow-up was 16 ±â€Š9 months. There was significant improvement in all cervical alignment parameters (segmental kyphosis, C2-7 SVA, cervical lordosis). No intraoperative complications occurred and no patient deteriorated neurologically postoperatively. Postoperative complications included anterior cage/graft dislodgement (n = 2), recurrent neck hematomas requiring revision (n = 1), epidural hematoma (n = 1), and wound infection (n = 1). Sixty percent of patients had persistent neurologic dysfunction at final follow-up. None required reoperation for recurrent infection or pseudarthrosis. CONCLUSION: Although overall prognosis and neurologic recovery are guarded in medically fragile patients with multilevel subaxial cervical osteomyelitis, reconstruction with multilevel (≥2) corpectomy and anterior reconstruction/plating results in excellent restoration of cervical alignment and low rates of recurrent infection and pseudarthrosis. LEVEL OF EVIDENCE: 4.

Economic Impact of Revision Surgery for Proximal Junctional Failure After Adult Spinal Deformity Surgery: A Cost Analysis of 57 Operations in a 10-year Experience at a Major Deformity Center.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To evaluate the economic impact of revision surgery for proximal junctional failures (PJF) after thoracolumbar fusions for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: PJF after fusions for ASD is a major cause of disability. Although clinical sequelae are described, PJF-revision operation costs are incompletely defined. METHODS: Consecutive adults who underwent thoracolumbar fusions for ASD (August, 2003 to January, 2013) were evaluated. Inclusion criteria include construct from pelvis to L2 or above and minimum 6 months follow-up after the index ASD operation. Direct costs (surgical supplies/implants, room/care, pharmacy, services) were identified from medical billing data and calculated for index ASD operations and subsequent surgeries for PJF. Not included in direct cost data were indirect costs, charges, surgeon fees, or revision operations for indications other than PJF (i.e., pseudarthrosis). Patients were compared based on the construct's upper-instrumented vertebra: upper thoracic (UT: T1-6) versus thoracolumbar junction (TLjxn: T9-L2). RESULTS: Of 501 patients, 382 met inclusion criteria. Fifty-one patients [UT:14; TLjxn: 40 at index; average follow-up 32.6 months (6-92 months)] had revisions for PJF, which summed to $3.2 million total direct cost. Average direct cost of index operations for the cohort ($68,294) was significantly greater than PJF-revisions ($55,547). Compared with TLjxn, UT had a significantly higher average cost for index operations ($79,860 vs. $65,868). However, PJF-revision cases were similar in average cost (UT:$60,103; TLjxn:$53,920; P = 0.09). Costs of PJF amounted to an additional 12.1% of the total index surgical cost in 382 patients. CONCLUSION: Revision operations for PJF after long thoracolumbar fusions for ASD are associated with an average direct cost of $55,547 per case. Revision costs for PJF are similar based on the index procedure's upper-instrumented vertebra level. At a major tertiary center over a 10-year period, PJF came at a very significant economic expense amounting to $3.2 million for 57 cases. LEVEL OF EVIDENCE: 3.

Comparison of Expandable and Fixed Interbody Cages in a Human Cadaver Corpectomy Model: Fatigue Characteristics.

STUDY DESIGN: In vitro cadaver biomechanics study. OBJECTIVE: The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. SUMMARY OF BACKGROUND DATA: Expandable cages are becoming more popular, in large part, due to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. METHODS: Nineteen specimens from 10 human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated after a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98 K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. RESULTS: Three fixed and 2 expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in after initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. CONCLUSIONS: Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared with fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages.

Anterior corpectomy via the mini-open, extreme lateral, transpsoas approach combined with short-segment posterior fixation for single-level traumatic lumbar burst fractures: analysis of health-related quality of life outcomes and patient satisfaction.

OBJECTIVE: The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures. METHODS: Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up. RESULTS: Twelve patients (7 men, 5 women, average age 42 years, range 22-68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5-8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16-68 months), and average radiographic follow-up was 37 months (range 6-68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0-52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery. CONCLUSIONS: Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Revision surgery for lumbar pseudarthrosis.

BACKGROUND CONTEXT: Revision surgery for pseudarthrosis after a lumbar spinal fusion has unpredictable functional results. PURPOSE: The aim of this study was to determine the clinical outcomes of revision surgery to fuse the pseudarthrosis site based on the two most common diagnoses (degenerative disc disease [DDD] vs. spondylolisthesis). STUDY DESIGN: Patients who had a revision surgery between 1995 and 2004 for lumbar pseudarthrosis after short segment lumbar spinal fusion were identified through the institution's Spine Center surgery database. A retrospective chart review of clinical, hospital, and anesthesia records was then performed. PATIENT SAMPLE: Sixty-six patients were included in the study (28 patients with DDD and 38 patients with spondylolisthesis). Inclusion criteria were a surgical diagnosis of pseudarthrosis with a prior fusion of one or two motion segments, minimum 24 months of follow-up, and a diagnosis of either symptomatic DDD or spondylolisthesis as the primary indication for the index fusion surgery. OUTCOME MEASURES: The Oswestry disability index (ODI) and a self-assessment questionnaire were used to evaluate clinical outcomes. METHODS: A retrospective chart and radiographic review was performed. Statistical analysis was done using Student t test for ODI scores and chi-square test for discrete variables from the outcome questionnaires. RESULTS: Follow-up radiographs were available for 64 patients (97%), and a fusion rate of 100% was found in both groups for the radiographs examined. The mean postoperative ODI score was 53.3 (30-84.4) for DDD patients and 37.2 (2.5-76) for the spondylolisthesis group (p<.01). Only 50% of the patients in the DDD group felt that their overall well-being had improved since the surgery. In the spondylolisthesis group, 64% of patients stated that their overall well-being had improved since their revision surgery. CONCLUSIONS: The clinical outcomes after revision surgery for pseudarthrosis are worse in patients with DDD compared with spondylolisthesis despite successful repair of nonunion. Risks and benefits should be well discussed with the patients before deciding on surgical treatment for the management of pseudarthrosis, especially in patients with previous short-segment fusions done for DDD.

Cervical spine clearance protocols in Level I, II, and III trauma centers in California.

BACKGROUND CONTEXT: Cervical spine clearance protocols were developed to standardize the clearance of the cervical spine after blunt trauma and prevent secondary neurologic injuries. The degree of incorporation of evidence-based guidelines into protocols at trauma centers in California is unknown. PURPOSE: To evaluate the cervical spine clearance protocols in all trauma centers of California. STUDY DESIGN: An observational cross-sectional study. PATIENT SAMPLE: Included from Level I, II, III trauma centers in California. OUTCOME MEASURES: The self-reported outcomes of each trauma center's cervical spine clearance protocols were assessed. METHODS: Level I (n=15), II (n=30), and III (n=11) trauma centers in California were contacted. Each available protocol was reviewed for four scenarios: clearing the asymptomatic patient, the initial imaging modality used in patients not amenable to clinical clearance, and the management strategies for patients with persistent neck pain with a negative computed tomography (CT) scan and those who are obtunded. Results were compared with the 2009 Eastern Association for the Surgery of Trauma (EAST) cervical spine clearance guidelines. RESULTS: The response rate was 96%. Sixty-three percent of California's trauma centers (Level I, 93%; Level II, 60%; Level III, 27%) had written cervical spine clearance protocols. For asymptomatic patients, 83% of Level I and 61% of Level II centers used National Emergency X-Radiography Utilization Study criteria with/without painless range of motion. For those requiring imaging, 67% of Level I and 56% of Level II centers stated a CT scan should be the first line of imaging. For obtunded patients and patients with persistent neck pain and a negative CT scan, more than 90% of Level I and more than 70% of Level II trauma centers incorporated the 2009 EAST recommendations. No institution recommended passive flexion-extension radiographs for the obtunded patient. CONCLUSIONS: Written cervical spine clearance protocols exist in 63% of California's trauma centers and only 51% of the centers have protocols that follow current evidence-based guidelines. Standardization and utilization of these protocols should be encouraged to prevent missed injuries and secondary neurologic injuries.

Local intrawound vancomycin powder decreases the risk of surgical site infections in complex adult deformity reconstruction: a cost analysis.

STUDY DESIGN: Retrospective cohort analysis. OBJECTIVE: To evaluate the rate of surgical site infections (SSIs) and cost-effectiveness of the use of intraoperative vancomycin powder in thoracolumbar adult deformity procedures. SUMMARY OF BACKGROUND DATA: The rates of SSI remain unacceptably high in adult spinal deformity surgery despite routine intravenous antibiotics. Vancomycin powder applied directly to the wound intraoperatively has shown promise for decreasing SSI in spine surgery. METHODS: Adults who underwent adult deformity reconstruction by 2 surgeons between 2008 and 2012 with a minimum of 3 months of clinical follow-up were retrospectively reviewed. The patients were subdivided into those who had received only routine perioperative intravenous antibiotics (control) and those who received intravenous antibiotics and 2 g of vancomycin powder applied into the surgical wound. The primary outcome was SSI within 90 days. Secondary outcomes included surgical/clinical parameters and SSI-related medical costs based on hospital billing records. RESULTS: Two hundred fifteen patients were evaluated-controls (n=64) and vancomycin powder group (n=151). The average number of levels fused was 10 (5-17, control) and 12 (5-19, vancomycin). The mean follow-up was 34 months (3-68 mo, control) and 18 months (3-35 mo, vancomycin) (P<0.05). There were significantly fewer hospital readmissions within 90 days for SSI in patients who received vancomycin powder (2.6%; 4/151) compared with controls (10.9%; 7/64) (P=0.01). There were no reported adverse events related to the intrawound vancomycin use. The average cost per patient of treating a postoperative SSI was higher in the control group ($34,388) than in the study group ($28,169). With the use of vancomycin powder, there was a cost saving of $244,402 per 100 complex spinal procedures. CONCLUSION: Local application of vancomycin powder significantly decreased SSI for adults undergoing spinal reconstructive surgery. This resulted in cost savings of $244,402 per 100 thoracolumbar adult deformity procedures. LEVEL OF EVIDENCE: 3.

Are conventional inlet and outlet radiographs obsolete in the evaluation of pelvis fractures?

INTRODUCTION: The new-generation multidetector computed tomographic (CT) scanners allow for the generation of virtual x-rays from the data acquired during the evaluation of pelvic fractures. Special software allows technicians to obtain the appropriate orientation required for adequate inlet and outlet views, which would eliminate repeat trips to the radiography suite to acquire adequate x-rays. The purpose of this study is to compare the quality virtual x-rays and conventional x-rays that are used in evaluating pelvis fractures. METHODS: A retrospective database review was performed to identify patients who were operated on with a diagnosis of pelvis fracture. The inclusion criteria were AO/OTA type B or C pelvic fractures, age older than 18 years, complete set of anteroposterior (AP) pelvis, inlet, and outlet x-rays and a multidetector pelvis CT scan. Virtual AP pelvis, inlet, and outlet views were generated from the CT scan data. Two fellowship-trained orthopedic trauma surgeons reviewed the virtual and conventional studies separately in association with CT scans and graded the quality of the studies on a custom developed questionnaire. RESULTS: Twenty patients were eligible for the study. The AP pelvis image quality was similar for both conventional and virtual images except for the rotation of the pelvis, which was improved in the virtual images. The inlet and outlet image quality was better in all domains in the virtual x-ray group when compared with the conventional x-rays. The percentage of adequate inlet and outlet images was higher in the virtual x-ray group when compared with the conventional x-ray group. DISCUSSION: The results show that the virtual inlet and outlet images consistently provided higher rates of adequate x-rays when compared with the conventional x-rays. In the evaluation of patients with pelvis fractures, the use of the virtual inlet and outlet views instead of the conventional x-rays may provide some advantages, such as decreased radiation exposure to the patient, reduced overall cost, and reduced repeat x-rays to achieve adequate views. LEVEL OF EVIDENCE: Diagnostic study, level V.

Surgical treatment of thoracic disc disease via minimally invasive lateral transthoracic trans/retropleural approach: analysis of 33 patients.

Thoracic disc herniations are associated with serious neurological consequences if not treated appropriately. Although a number of techniques have been described, there is no consensus about the best surgical approach. In this study, the authors report their experience in the operative management of patients with thoracic disc herniations using minimally invasive lateral transthoracic trans/retropleural approach. A series of 33 consecutive patients with thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through lateral approach is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed. Forty disc levels in 33 patients (18F/15M; mean age, 52.9) were treated. Twenty-three patients presented with myelopathy (69 %), 31 had radiculopathy (94 %), and 31 had axial pain (94 %). Among patients with myelopathy, 14 (42.4 %) had bladder and/or bowel dysfunction. In the last eight cases (24 %), the approach was retropleural instead of transpleural. Patients were followed up for 18.2 months on average. The mean length of hospital stay was 5 days. None of the patients developed neurological deterioration postoperatively. Among 23 patients who had myelopathy signs, 21 (91 %) had improved postoperatively. The mean preoperative visual analog scale pain score, Oswestry Disability Index score, SF-36 PCS, and mental component summary scores were 7.5, 42.4, 29.6, and 37.5 which improved to 3.5, 33.2, 35.5, and 52.6, respectively. Perioperative complications occurred in six patients (18.1 %), all of which resolved uneventfully. Minimally invasive lateral transthoracic trans/retropleural approach is a safe and efficacious technique for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional approaches.

Construct Rigidity after Fatigue Loading in Pedicle Subtraction Osteotomy with or without Adjacent Interbody Structural Cages.

Introduction Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods Twelve specimens received bilateral T12-S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2-L3 and L3-L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2-L4) and entire fixation site (T12-S1) was measured. All specimens were then fatigue tested for 35K cycles. Results Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2-L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant (p = 0.095), was 22.2% greater in the PSO + XLIF group than in the PSO-only group. Conclusions Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this.

Minimal invasive anterolateral transthoracic transpleural approach: a novel technique for thoracic disc herniation. A review of the literature, description of a new surgical technique and experience with first 12 consecutive patients.

STUDY DESIGN: A retrospective review of a case series. OBJECTIVE: To describe a novel surgical technique for a minimally disruptive lateral transthoracic transpleural approach to treat thoracic disc herniations. SUMMARY OF BACKGROUND DATA: Thoracic disc herniation is a relatively uncommon spinal condition, and surgical treatment is indicated for patients with myelopathy or radiculopathy that failed to respond to conservative therapy. Presently there is no consensus about the best approach to address thoracic disc herniations. Using the novel retractor system (MaXcess), the authors describe a novel minimally disruptive approach that allows the surgeons to perform a standard anterior discectomy and fusion with instrumentation while minimizing approach-related morbidity. METHODS: A series of 12 patients with single-level thoracic disc herniations who underwent anterior spinal cord decompression followed by instrumented fusion through a novel retractor system is being reported. Demographic and radiographic data, perioperative complications, and clinical outcomes were reviewed. RESULTS: Twelve patients were enrolled with an average age of 51 years (range, 23 to 67 y). The average follow-up was 28 months (range, 12 to 33 mo). The average length of hospital stay was 5 days (range, 2 to 12 d). The average preoperative visual analog scale pain score was 9 (range, 7 to 10), which later decreased to 3 (range, 0 to 5) at final follow-up. All patients with myelopathy and/or sphincter dysfunction had significant improvement of their symptoms. One patient had pleural effusion and 1 patient had intercostal neuralgia. CONCLUSIONS: Anterior decompression using a transthoracic transpleural approach provides excellent exposure and allows consistent decompression of thoracic disc herniations. This study demonstrated that a new minimally invasive, transthoracic transpleural decompression technique can be safely performed for single-level thoracic disc herniations. The early results showed that this technique allows less dissection, along with the advantages of conventional thoracotomy.

Biomechanical analysis of revision strategies for rod fracture in pedicle subtraction osteotomy.

BACKGROUND: Pseudoarthrosis after pedicle subtraction osteotomy (PSO) can require revision surgery due to posterior rod failure, and the stiffness of these revision constructs has not been quantified. OBJECTIVE: To compare the multidirectional bending stiffness of 7 revision strategies following rod failure. METHODS: Seven fresh-frozen human spines (T11-pelvis) were tested as follows: (1) posterior instrumentation from T12-S1 (excluding L3) with iliac fixation and L3 PSO; (2) inline connectors after rod breakage at L3 (L2 screws removed for access); (3) cross-links connecting rods above and below inline connectors; satellite rods (4) parallel, (5) 45° anterior, and (6) 45° posterior to original rods; 45° posterior with cross-links connecting (7) original and (8) satellite rods. Groups 3 to 8 were tested in random order. Nondestructive pure moment flexion-extension (FE), lateral bending (LB), and axial rotation (AR) tests were conducted to 7.5 Nm; 3D motion tracking monitored the primary range of motion. RESULTS: Addition of inline connectors alone restored stiffness in FE and LB (P > .05), but not in AR (P < .05). Satellite rods (groups 4 to 6) restored stiffness in FE and LB (P > .05), but not in AR (P < .05) and were not significantly different from one another (P > .05). The addition of cross-links (groups 3, 7, and 8) restored stiffness in all bending modes (P > .05) and were significantly greater than inline connectors alone in AR (P < .05). CONCLUSION: The results suggest that these revision strategies can restore stiffness without entire rod replacement. Failure of AR stiffness restoration can be mitigated with cross-links. The positioning of the satellite rods is not an important factor in strengthening the revision.

Osseous remodeling after femoral head-neck junction osteochondroplasty.

UNLABELLED: Femoral head-neck junction osteochondroplasty is commonly used to treat femoroacetabular impingement, yet remodeling of the osteochondroplasty site is not well described. We therefore describe bony remodeling at the osteochondroplasty site and analyze clinical outcomes and complications associated with femoral osteochondroplasty. We retrospectively reviewed 135 patients (150 hips) who underwent femoral head-neck osteochondroplasty combined with hip arthroscopy, surgical hip dislocation, periacetabular osteotomy, or proximal femoral osteotomy. The minimum clinical followup was 10 months (mean, 22.3 months; range, 10-65 months). We assessed the femoral-head neck offset, head-neck offset ratio, alpha angle, and cortical remodeling. We used the Harris hip score to determine hip function. We observed an increase in the head-neck offset, offset ratio, and decrease in the alpha angle postoperatively and at latest followup. Ninety-eight of 113 (87%) hips had partial or complete recorticalization at the osteochondroplasty site. The mean Harris hip score improved from 64 to 85. We excised heterotopic bone in one hip. There were no femoral neck fractures. The deformity correction achieved with femoral head-neck osteochondroplasty is maintained and recorticalization occurs in the majority of cases during the first two years. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

The effect of anterior spinal fusion on spinal canal development in an immature porcine model.

STUDY DESIGN: Experimental study. OBJECTIVE: To investigate whether anterior spine fusion in the immature porcine spine has an adverse effect on the development of spinal canal. SUMMARY OF BACKGROUND DATA: Neurocentral cartilage (NCC) is located in the posterior vertebral body and responsible for the development of posterior aspect of the spinal canal. Injury to the NCC interferes with the development of the spinal canal. METHODS: Twelve 8-week-old domestic pigs were used to develop an anterior fusion model. A standard procedure as L3-L4, L4-L5 discectomy, and L3-L5 anterior instrumented spine fusion was performed. To evaluate the development of the spinal canal, all subjects had computed tomography scans before the procedure and at the final follow-up. The spinal canal area was measured at the control level (CL) (L2), arthrodesis level (AL) (L4), superior (L3), and inferior (L5) instrumented level (SIL and IIL). Percent change in spinal canal area from before surgery to final follow-up was also calculated. RESULTS.: Eleven subjects were available for the study. All subjects developed local kyphosis over the fused segments. The average area of L2 (CL) was 0.56 +/- 0.06 cm before surgery. The average areas of the L3 (SIL), L4 (AL), and L5 (IIL) were 0.62, 0.70, and 0.77 cm, respectively. At the final follow-up the average area of L2 was 1.20 cm. The average areas of the SIL, AL, and IIL were 1.16, 1.19, and 1.33 cm, respectively. The percent increase in spinal canal area at the CL was 116.6% whereas it was 85.8%, 71.0%, and 71.2% at SIL, AL, and IIL, respectively. CONCLUSION: Anterior spinal arthrodesis in the immature porcine spine results in iatrogenic retardation on spinal canal growth. This effect is most likely related to the tethering effect of the interbody fusion over the NCC. Although, it is difficult to directly extrapolate these findings to clinical practice, the spine surgeons operating on pediatric patients should be aware of this possibility.