Category: Spine

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Optimal Timing of Surgical Decompression for Acute Traumatic Central Cord Syndrome

central cord syndrome

Neurosurgery 77:S15–S32, 2015

Traumatic central cord syndrome (TCCS) is an incomplete spinal cord injury defined by greater weakness in upper versus lower extremities, variable sensory loss, and variable bladder, bowel, and sexual dysfunction. The optimal timing of surgery for TCCS remains controversial.

OBJECTIVE: To determine whether timing of surgery for TCCS predicts neurological outcomes, length of stay, and complications.

METHODS: Five databases were searched through March 2015. Articles were appraised independently by 2 reviewers, and the evidence synthesized according to Grading of Recommendation Assessment, Development and Evaluation principles.

RESULTS: Nine studies (3 prognostic, 5 therapeutic, 1 both) satisfied inclusion criteria. Low level evidence suggests that patients operated on ,24 hours after injury exhibit significantly greater improvements in postoperative American Spinal Injury Association motor scores and the functional independence measure at 1 year than those operated on .24 hours after injury. Moderate evidence suggests that patients operated on >2 weeks after injury have a higher postoperative Japanese Orthopaedic Association score and recovery rate than those operated on >2 weeks after injury. There is insufficient evidence that lengths of hospital or intensive care unit stay differ between patients who undergo early versus delayed surgery. Furthermore, there is insufficient evidence that timing between injury and surgery predicts mortality rates or serious or minor adverse events.

CONCLUSION: Surgery for TCCS <24 hours after injury appears safe and effective. Although there is insufficient evidence to provide a clear recommendation for early surgery (<24 hours), it is preferable to operate during the first hospital admission and <2 weeks after injury.

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A Systematic Review of the Treatment of Geriatric Type II Odontoid Fractures

Type II Odontoid Fractures

Neurosurgery 77:S6–S14, 2015

Odontoid fractures are the most common cervical spine fracture in the geriatric population; however, the treatment of type II odontoid fractures in this age group is controversial.

OBJECTIVE: To compare the short-term (<3 months) mortality, long-term (≥12 months) mortality, and complication rates of patients >60 years of age with a type II odontoid fracture managed either operatively or nonoperatively.

METHODS: We performed a systematic review of literature published between January 1, 2000, and February 1, 2015, related to the treatment of type II odontoid fractures in patients .60 years of age. An analysis of short-term mortality, long-term mortality, and the occurrence of complications was performed.

RESULTS: A total of 452 articles were identified, of which 21 articles with 1233 patients met the inclusion criteria. Short-term mortality (odds ratio, 0.43; 95% confidence interval, 0.30-0.63) and long-term mortality (odds ratio, 0.47; 95% confidence interval, 0.34-0.64) were lower in patients who underwent surgical treatment than in those who had nonsurgical treatment, and there were no significant differences in the rate of complications (odds ratio, 1.01; 95% confidence interval, 0.63-1.63). Surgical approach (posterior vs anterior) showed no significant difference in mortality or complication rate. Similarly, no difference in mortality or complication rate was identified with hard collar or a halo orthosis immobilization.

CONCLUSION: The current literature suggests that well-selected patients >60 years of age undergoing surgical treatment for a type II odontoid fracture have a decreased risk of short-term and long-term mortality without an increase in the risk of complications.

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Unskilled unawareness and the learning curve in robotic spine surgery

SpineAssist™ robot system

Acta Neurochir (2015) 157:1819–1823

Robotic assistance for the placement of pedicle screws has been established as a safe technique. Nonetheless rare instances of screw misplacement have been reported.The aim of the present retrospective study is to assess whether experience and time affect the accuracy of screws placed with the help of the SpineAssist™ robot system.

Methods Postoperative computed tomography (CT) scans of 258 patients requiring thoracolumbar pedicle screw instrumentation from 2008 to 2013 were reviewed. Overall, 13 surgeons performed the surgeries. A pedicle breach of >3 mm was graded as a misplacement. Surgeons were dichotomised into an early and experienced period in increments of five surgeries.

Results In 258 surgeries, 1,265 pedicle screws were placed with the aid of the robot system. Overall, 1,217 screws (96.2 %) were graded as acceptable. When displayed by surgeon, the development of percent misplacement rates peaked between 5 and 25 surgeries in 12 of 13 surgeons. The overall misplacement rate in the first five surgeries was 2.4%(6/245). The misplacement rate rose to 6.3 % between 11 and 15 surgeries (10/158; p=0.20), and reached a significant peak between 16 and 20 surgeries with a rate of 7.1 % (8/112; p= 0.03). Afterwards, misplacement rates declined.

Conclusions A major peak in screw inaccuracies occurred between cases 10 and 20, and a second, smaller one at about 40 surgeries. One potential explanation could be a transition from decreased supervision (unskilled but aware) to increased confidence of a surgeon (unskilled but unaware) who adopts this new technique prior to mastering it (skilled). We therefore advocate ensuring competent supervision for new surgeons at least during the first 25 procedures of robotic spine surgery to optimise the accuracy of robot-assisted pedicle screws.

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Management of the Elderly With Vertebral Compression Fractures

Management of the Elderly With Vertebral Compression Fractures

Neurosurgery 77:S33–S45, 2015

Vertebral compression fractures (VCFs) are the most common type of fracture secondary to osteoporosis. These fractures are associated with significant rates of morbidity and mortality and annual direct medical expenditures of more than $1 billion in the United States. Although many patients will respond favorably to nonsurgical care of their VCF, contemporary natural history data suggest that more than 40% of patients may fail to achieve significant pain relief within 12 months of symptom onset. As a result, percutaneous vertebral augmentation is often used to hasten symptom resolution and return of function. However, controversy regarding the role of kyphoplasty and vertebroplasty in the treatment of symptomatic VCFs exists.

The purposes of this review are (1) to outline the epidemiology of VCFs as well as the physical morbidity and economic impact of these injuries, (2) to familiarize the reader with the best available evidence surrounding the operative and nonoperative treatment of VCFs, and (3) to examine the literature pertaining to the cost-effectiveness of surgical management of VCFs with the overarching goal of helping physicians make informed decisions regarding symptomatic VCF treatment.

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Minimally Invasive Spinal Surgery in the Elderly: Does It Make Sense?

Minimally Invasive Spinal Surgery in the Elderly- Does It Make Sense

Neurosurgery 77:S108–S115, 2015

Lumbar degenerative disease can have varied pathoanatomy, with stenosis, spondylolisthesis, and scoliosis contributing to significant pain and disability. Among appropriately selected patients, surgical intervention can treat both back pain and leg pain and improve quality of life in a cost-effective manner with an acceptable safety profile. The evolution of minimally invasive surgical (MIS) techniques offers the potential to decrease the physiological impact of surgery and to improve the complication profile while achieving the same spine surgical objectives. The utility of such techniques among elderly patients >65 years of age has not been rigorously evaluated, and this systematic review sought to define the utility and safety of MIS spinal surgery for decompression, interbody fusion, and deformity correction in this population.

Review of 2 studies for MIS lumbar decompression reveals that the majority of elderly patients exhibit significant improvements in pain (change in visual analog score for leg pain, 3.4 points) and disability (change in Oswestry Disability Index, 19 points), with inadvertent durotomy in 3% of patients. Review of 4 studies for MIS lumbar interbody fusion reveals robust improvement in pain (change in visual analog score for leg pain, 3.4 points; change in visual analog score for back pain, 7.2 points), with inadvertent durotomy in 5% of patients.

Narrative review was performed for adult degenerative deformity correction, revealing that MIS techniques are feasible for managing such patients with acceptable rates of osseous union and complication. On the basis of largely low-quality, retrospective evidence, we recommend that elderly patients should not be excluded from MIS interventions for symptomatic lumbar degenerative spinal disease.

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Two-level corpectomy versus three-level discectomy for cervical spondylotic myelopathy

Two-level corpectomy versus three-level discectomy for cervical spondylotic myelopathy

J Neurosurg Spine 23:280–289, 2015

In the treatment of cervical spondylotic myelopathy (CSM), anterior cervical corpectomy and fusion (ACCF) and anterior cervical discectomy and fusion (ACDF) are effective decompressive techniques. It remains to be determined whether ACCF and ACDF offer equivalent outcomes for multilevel CSM. In this study, the authors compared perioperative, radiographic, and clinical outcomes between 2-level ACCF and 3-level ACDF.

Methods Between 2006 and 2012, all patients at the authors’ hospital who underwent 2-level ACCF or 3-level ACDF performed by 1 of 2 surgeons were identified. Primary outcomes of interest were sagittal Cobb angle, adjacent-segment disease (ASD) requiring surgery, neck pain measured by visual analog scale (VAS), and Nurick score. Secondary outcomes of interest included estimated blood loss (EBL), length of stay, perioperative complications, and radiographic pseudarthrosis rate. Chi-square tests and 2-tailed Student t-tests were used to compare the 2 groups. A subgroup analysis of patients without posterior spinal fusion (PSF) was also performed.

Results Twenty patients underwent 2-level ACCF, and 35 patients underwent 3-level ACDF during a 6-year period. Preoperative Nurick scores were higher in the ACCF group (2.1 vs 1.1, p = 0.014), and more patients underwent PSF in the 2-level ACCF group compared with patients in the 3-level ACDF group (60.0% vs 17.1%, p = 0.001). Otherwise there were no significant differences in demographics, comorbidities, and baseline clinical parameters between the 2 groups. Two-level ACCF was associated with significantly higher EBL compared with 3-level ACDF for the anterior stage of surgery (382.2 ml vs 117.9 ml, p < 0.001). Two-level ACCF was also associated with a longer hospital stay compared with 3-level ACDF (7.2 days vs 4.9 days, p = 0.048), but a subgroup comparison of patients without PSF showed no significant difference in length of stay (3.1 days vs 4.4 days for 2-level ACCF vs 3-level ACDF, respectively; p = 0.267). Similarly, there was a trend toward more complications in the 2-level ACCF group (20.0%) than the 3-level ACDF group (5.7%; p = 0.102), but a subgroup analysis that excluded those who had second-stage PSF no longer showed the same trend (2-level ACCF, 0.0% vs 3-level ACDF, 3.4%; p = 0.594). There were no significant differences between the ACCF group and the ACDF group in terms of postoperative sagittal Cobb angle (7.2° vs 12.1°, p = 0.173), operative ASD (6.3% vs 3.6%, p = 0.682), and radiographic pseudarthrosis rate (6.3% vs 7.1%, p = 0.909). Both groups had similar improvement in mean VAS neck pain scores (3.4 vs 3.2 for ACCF vs ACDF, respectively; p = 0.860) and Nurick scores (0.8 vs 0.7, p = 0.925).

Conclusions Two-level ACCF was associated with greater EBL and longer hospital stays when patients underwent a second-stage PSF. However, the length of stay was similar when patients underwent anterior-only decompression with either 2-level ACCF or 3-level ACDF. Furthermore, perioperative complication rates were similar in the 2 groups when patients underwent anterior decompression without PSF. Both groups obtained similar postoperative cervical lordosis, operative ASD rates, radiographic pseudarthrosis rates, neurological improvement, and pain relief.

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Factors that may affect outcome in cervical artificial disc replacement: a systematic review

Analysis of in vivo kinematics of 3 different cervical devices- Bryan disc, ProDisc-C, and Prestige LP dis

Eur Spine J (24)9:2023-2032

To identify the factors that may affect outcome in C-ADR and provide the pooled results of postoperative success rate of implanted segment range of motion (ROM), incidence of heterotopic ossification (HO), incidence of radiographic adjacent segment degeneration (r-ASD)/adjacent segment disease (ASD), and surgery rate for ASD.

Methods

We systematically searched in PubMed, Embase, Cochrane library and Web of knowledge from 2001 to May 2015. Two independent reviewers screened the primary records. Eleven questions regarding the effect of patient selection issues and radiographic parameters issues on outcome were posed previously. Studies addressing the framed questions were included for analysis.

Results

Twenty-two studies were included for the final analysis. Results showed that number of surgical level (single versus double-level) had no effect on primary clinical outcome and radiographic outcome, surgical level had no effect on clinical and radiographic outcome, and smoking habits had negative effect on clinical outcome. No evidence for the effect of patient’s age and pathology category (radiculopathy or myelopathy) on outcome was found. The overall success rate of ROM was 79.4 %. ROM of the implanted segment and cervical sagittal alignment had no effects on clinical outcome. The pooled incidences of grade 1–4 HO and grade 3–4 HO were 27.7 and 7.8 %, respectively. The pooled incidence of r-ASD and surgery rate for ASD were 42.4 and 3.8 %, respectively.

Conclusions

The available evidence showed that most of the pre-selected factors had no effect on outcome after C-ADR, and the ROM success rate, incidence of HO and r-ASD/ASD, and surgery rate for ASD are acceptable. There is a lack of evidence from RCTs for some factors.

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Impact of Age on Short-term Outcomes After Lumbar Fusion

Three-Dimensional Computed Tomography-Based Spinal Navigation in Minimally Invasive Lateral Lumbar Interbody Fusion4

Neurosurgery 77:347–354, 2015

The safety and efficacy of spinal fusion in the elderly population remains uncertain with conflicting data.

OBJECTIVE: To determine if elderly patients undergoing instrumented lumbar fusion have increased 30-day complication rates compared to younger patients.

METHODS: The American College of Surgeons National Surgical Quality Improvement Program was used to identify all patients undergoing instrumented posterolateral lumbar fusion between 2005 and 2011. Patients were stratified by decade cohorts as follows: ,65, 65 to 75, 75 to 85, and $85 years old. All 30-day complications were grouped as overall composite morbidity and were compared using multivariate analysis.

RESULTS: A total of 1395 patients were identified and the overall 30-day complication rate was 11.47%. The complication rates were 9.04% and 14.05% for patients younger than 65 and older than 65, respectively. When stratified by decade cohorts, the complication rates were 9.04% for the ,65 cohort, 13.46% for the 65 to 75 cohort, 16.17% for the .75 to 85 cohort, and 4.00% for the $85 cohort. Multivariable regression analysis revealed no statistically significant difference between the ,65 and $65 age cohorts (odds ratio = 1.26; 95% confidence interval: 0.87-2.19). After stratifying into age cohorts, multivariable analyses revealed no difference in odds of postoperative complication occurrence for any age cohort when compared with the referent group (,65 years of age).

CONCLUSION: Patients older than 65 years of age have significantly higher rates of complications after lumbar fusion when compared to younger patients. However, multivariable analysis revealed that age was not an independent risk factor for complication occurrence after lumbar fusion.

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Bifid Anterior and Posterior Arches of Atlas

Bifid Anterior and Posterior Arches of Atlas- Surgical Implication and Analysis of 70 Cases

Neurosurgery 77:296–306, 2015

On reviewing the database of patients with craniovertebral junction anomalies, the authors identified 70 patients with a bifid posterior arch of atlas.

OBJECTIVE: To speculate on the pathogenesis of spondyloschisis of both the anterior and posterior arches of atlas, particularly as it relates to atlantoaxial instability.

METHODS: Seventy patients with bifid anterior and posterior arches were identified by a retrospective review of the database from 2007 to 2013.

RESULTS: The ages of the patients ranged from 14 months to 50 years. The patients were divided into 3 groups. Group 1 (3 patients) had multiple additional spinal bony and neural abnormalities. Group 2 (34 patients) had mobile and partially (5) or completely (29) reducible atlantoaxial dislocation. Group 3 (33 patients) had atlantoaxial instability and related basilar invagination. The os odontoideum was identified in 21 patients, and C2-3 fusion was seen in 24 patients. Two of 3 patients in group 1 were treated conservatively and without any surgery. All patients in groups 2 and 3 were surgically treated. Surgery was done using lateral mass plate/rod and screw fixation techniques. The general observation during surgery included identification of discrete movements of both halves of the atlas, lateral positioning of the facets of atlas in relation to the facets of the axis and occipital condyle and closer approximation of the occipital bone, atlas, and axis resulting in “crumpling” of bone and neural elements.

CONCLUSION: Understanding of the pathogenesis and mechanical alterations in cases with a bifid arch of atlas can assist in evaluating the clinical implications and in conduct of surgery.

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The relationship between laminoplasty opening angle and increased sagittal canal diameter and the prediction of spinal canal expansion following double-door cervical laminoplasty

Laminoplasty formula

Eur Spine J (2015) 24:1597–1604

To clarify the relationship between laminoplastyopening angle (LOA) and the increase in sagittal canaldiameter (SCD) in double-door cervical laminoplasty(DDCL) and to predict the increase in SCD using the resulting formula.

Methods We analyzed 20 patients with multilevel cervical spondylotic myelopathy who underwent DDCL between September 2010 and January 2013. The pre- and post-operative parameters of the cervical spinal canal were measured by computed tomography. We deduced a formula describing the relationship between LOA and the increase in SCD and used it to predict the increase in SCD of these patients as LOA increased.

Results When the C3–C7 LOA was 25º–45º, the magnitude of the increase in SCD was notable (increases of 3.08–5.6 mm compared with the pre-operative SCD).When the C3–C7 LOA was more than 45º, the magnitude of the increase in SCD was relatively smaller; the increase in C3–C7 SCD with a 55º LOA was merely 0.4 mm more than with a 45º LOA. When LOA was 30º at C3–C6 or 40º at C7, the increase in SCD was more than 4 mm. When the C3–C6 LOA was 40º, SCD increased by more than 5 mm.

Conclusions The formula accurately showed the relationship between LOA and the increase in SCD in DDCL. Based on the LOA, increases in SCD following C3–C7 laminoplasty can be accurately predicted using this formula. This enables DDCL based on accurate individual LOAs, which prevents inadequate or excessive opening.

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The Mechanism of Ligamentum Flavum Hypertrophy

Ligamentum Flavum Hypertrophy

Neurosurgery 77:274–282, 2015

Biochemical alterations associated with mechanical stress have been explored as an initiating step in the pathological progression of ligamentum flavum hypertrophy (LFH); however, this mechanism remains poorly understood. Recently, the inflammation induced after mechanical stress and the subsequent response of ligamentum flavum (LF) cells have been implicated in LFH pathology.

OBJECTIVE: To investigate the hypothesis that angiogenesis may be a critical link between hypertrophy and a series of stimulating events, including mechanical stress.

METHODS: LF from 20 lumbar spinal canal stenosis (LSCS) patients and 16 non-LSCS patients (control group) were collected during surgery. Patient demographic and radiographic data were obtained. The levels of angiogenic factors (vascular endothelial growth factor [VEGF], angiopoietin-1, vascular cell adhesion molecule, and basic fibroblast growth factor) in the LF were investigated by using an enzyme-linked immunosorbent assay. Angiogenesis was also quantified by immunohistochemical detection of CD34-positive capillaries. The correlations among clinical factors, including radiographic factors, angiogenic factors, and angiogenesis, were statistically analyzed.

RESULTS: The LSCS group was older and exhibited a longer symptom duration, wider segmental motion, and thicker LF than the control group. The LSCS group showed significantly higher tissue concentrations of VEGF (P , .001) that positively correlated with LF thickness (r = 0.557, P , .001) and segmental motion (r = 0.586, P , .001). The LSCS group showed significantly more CD34-positive capillaries than the control group (P = .004).

CONCLUSION: The LSCS group showed greater segmental motion, higher VEGF concentrations, and more CD34-positive capillaries than the control group. These data indicate that VEGF-mediated angiogenesis following mechanical stress may be a critical step within the series of pathological events in LFH.

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Posterior thoracic corpectomy with cage reconstruction for metastatic spinal tumors

mini-open and open transpedicular corpectomy

J Neurosurg Spine 23:217–227, 2015

Spinal metastases most commonly affect the vertebral bodies of the spinal column, and spinal cord compression is an indication for surgery. Commonly, an open posterior approach is employed to perform a transpedicular costotransversectomy or lateral extracavitary corpectomy. Because of the short life expectancies in patients with metastatic spinal disease, decreasing the morbidity of surgical treatment and recovery time is critical. One potential approach to decreasing morbidity is utilizing minimally invasive surgery (MIS). Although significant advances have been made in MIS of the spine, data supporting the utility of MIS are still emerging. This study compared outcomes of patients who underwent mini-open versus traditional open transpedicular corpectomy for spinal metastases in the thoracic spine.

Methods A consecutive cohort from 2006 to 2013 of 49 adult patients who underwent thoracic transpedicular corpectomies for spinal metastases was retrospectively identified. Patients were categorized into one of 2 groups: open surgery and mini-open surgery. Mini-open transpedicular corpectomy was performed with a midline fascial incision over only the corpectomy level of interest and percutaneous instrumentation above and below that level. The open procedure consisted of a traditional posterior transpedicular corpectomy. Chi-square test, 2-tailed t-test, and ANOVA models were employed to compare perioperative and follow-up outcomes between the 2 groups.

Results In the analysis, there were 21 patients who had mini-open surgery and 28 patients who had open surgery. The mean age was 57.9 years, and 59.2% were male. The tumor types encountered were lung (18.3%), renal/bladder (16.3%), breast (14.3%), hematological (14.3%), gastrointestinal tract (10.2%), prostate (8.2%), melanoma (4.1%), and other/unknown (14.3%). There were no significant intergroup differences in demographics, comorbidities, neurological status (American Spinal Injury Association [ASIA] grade), number of corpectomies performed, and number of levels instrumented. The open group had a mean operative time of 413.6 minutes, and the mini-open group had a mean operative time of 452.4 minutes (p = 0.329). Compared with the open group, the mini-open group had significantly less blood loss (917.7 ml vs 1697.3 ml, p = 0.019) and a significantly shorter hospital stay (7.4 days vs 11.4 days, p = 0.001). There was a trend toward a lower perioperative complication rate in the mini-open group (9.5%) compared with the open group (21.4%), but this was not statistically significant (p = 0.265). At follow-up, there were no significant differences in ASIA grade (p = 0.342), complication rate after the 30-day postoperative period (p = 0.999), or need for surgical revision (p = 0.803). The open approach had a higher overall infection rate of 17.9% compared with that in the mini-open approach of 9.5%, but this was not statistically significant (p = 0.409).

Conclusions The mini-open transpedicular corpectomy is associated with less blood loss and shorter hospital stay compared with open transpedicular corpectomy. The mini-open corpectomy also trended toward lower infection and complication rates, but these did not reach statistical significance.

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Venous organization in the transverse foramen

Venous organization in the transverse foramen

J Neurosurg 123:118–125, 2015

The anatomical arrangement of the venous system within the transverse foramen is controversial; there is disagreement whether the anatomy consists of a single vertebral vein or a confluence of venous plexus. Precise knowledge of this arrangement is necessary in imaging when vertebral artery dissection is suspected, as well as in surgical approaches for the cervical spine. This study aimed to better explain anatomical organization of the venous system within the transverse foramen according to the Trolard hypothesis of a transverse vertebral sinus.

Methods This was an anatomical and radiological study. For the anatomical study, 10 specimens were analyzed after vascular injection. After dissection, histological cuts were prepared. For the radiological study, a high-resolution MRI study with 2D time-of-flight segment MR venography sequences was performed on 10 healthy volunteers.

Results Vertebral veins are arranged in a plexiform manner within the transverse canal. This arrangement begins at the upper part of the transverse canal before the vertebral vein turns into a single vein along with the vertebral artery running from the transverse foramen of the C-6. This venous system runs somewhat ventrolaterally to the vertebral artery. In most cases, this arrangement is symmetrical and facilitates radiological readings. The anastomoses between vertebral veins and ventral longitudinal veins are uniform and arranged segmentally at each vertebra.

Conclusions These findings confirm recent or previous anatomical descriptions and invalidate others. It is hard to come up with a common description of the arrangement of vertebral veins. The authors suggest providing clinicians as well as anatomists with a well-detailed description of components essential to the understanding of this organization.

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A single-stage posterior approach with open reduction and pedicle screw fixation in subaxial cervical facet dislocations

A single-stage posterior approach with open reduction and pedicle screw fixation in subaxial cervical facet dislocations

J Neurosurg Spine 23:35–41, 2015

The optimal treatment for cervical facet dislocations is controversial, but the generally accepted process recommends an initial closed reduction with the next step determined according to the success of the closed reduction and the presence of traumatic disc herniation. This study aimed to show the efficacy of a posterior approach performed with an open reduction and pedicle screw fixation with removal of disc particles, if required, in the management of subaxial cervical dislocations.

Methods Between March 2012 and September 2013, 21 consecutive patients with cervical facet dislocations were enrolled. The affected levels were as follows: 4 at C3–4; 2 at C4–5; 5 at C5–6; and 10 at the C6–7 level. Seven patients had traumatic disc herniations. Closed reduction was not attempted; a prompt posterior cervical surgery was performed instead. After open reduction, pedicle screw fixation was performed. In cases with traumatic disc herniation, herniated disc fragments were excised via a posterolateral approach and successful decompressions were determined by postoperative MRI studies. Clinical outcomes were assessed using the American Spinal Injury Association (ASIA) grading system. Radiological outcomes were assessed by comparing the degree of subluxation and the angle of segmental lordosis between pre- and postoperative CT scans.

Results All patients improved neurologically. The mean segmental angles improved from 7.3° ± 8.68° to -5.9° ± 4.85°. The mean subluxation improved from 23.4% ± 16.52% to 2.6% ± 7.19%. Disc fragments were successfully removed from the 7 patients with herniated discs, as shown on MRI.

Conclusions Open reduction followed by pedicle screw fixation or posterolateral removal of herniated disc fragments is a good treatment option for cervical facet dislocations.

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Spinal sagittal balance and microendoscopic laminotomy

Spinal sagittal balance and microendoscopic laminotomy

J Neurosurg Spine 23:49–54, 2015

More information about the association between preoperative anterior translation of the C-7 plumb line and clinical outcomes after decompression surgery in patients with lumbar spinal canal stenosis (LSS) would help resolve problems for patients with sagittal imbalance. The authors evaluated whether preoperative sagittal alignment of the spine affects low-back pain and clinical outcomes after microendoscopic laminotomy.

Methods This study was a retrospective review of prospectively collected surgical data. The study comprised 88 patients with LSS (47 men and 41 women) who ranged in age from 39 to 86 years (mean age 68.7 years). All patients had undergone microendoscopic laminotomy at Osaka City University Graduate School of Medicine from May 2008 through October 2012. The minimum duration of clinical and radiological follow-up was 6 months. All patients were evaluated by Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores for low-back pain, leg pain, and leg numbness before and after surgery. The distance between the C-7 plumb line and the posterior corner of the sacrum (sagittal vertical axis [SVA]) was measured on lateral standing radiographs of the entire spine obtained before surgery. Radiological factors and clinical outcomes were compared between patients with a preoperative SVA ≥ 50 mm (forwardbending trunk [F] group) and patients with a preoperative SVA < 50 mm (control [C] group). A total of 35 patients were allocated to the F group (19 male and 16 female) and 53 to the C group (28 male and 25 female).

Results The mean SVA was 81.0 mm for patients in the F group and 22.0 mm for those in the C group. At final followup evaluation, no significant differences between the groups were found for the JOA score improvement ratio (73.3% vs 77.1%) or the VAS score for leg numbness (23.6 vs 24.0 mm); the VAS score for low-back pain was significantly higher for those in the F group (21.1 mm) than for those in the C group (11.0 mm); and the VAS score for leg pain tended to be higher for those in the F group (18.9 ± 29.1 mm) than for those in the C group (9.4 ± 16.0 mm).

Conclusions Preoperative alignment of the spine in the sagittal plane did not affect JOA scores after microendoscopic laminotomy in patients with LSS. However, low-back pain was worse for patients with preoperative anterior translation of the C-7 plumb line than for those without.

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Cervical laminoplasty developments and trends, 2003–2013: a systematic review

Laminoplasty

J Neurosurg Spine 23:24–34, 2015

Despite extensive clinical experience with laminoplasty, the efficacy of the procedure and its advantages over laminectomy remain unclear. Specific clinical elements, such as incidence or progression of kyphosis, incidence of axial neck pain, postoperative cervical range of motion, and incidence of postoperative C-5 palsies, are of concern. The authors sought to comprehensively review the laminoplasty literature over the past 10 years while focusing on these clinical elements.

Methods The authors conducted a literature search of articles in the Medline database published between 2003 and 2013, in which the terms “laminoplasty,” “laminectomy,” and “posterior cervical spine procedures” were used as key words. Included was every single case series in which patient outcomes after a laminoplasty procedure were reported. Excluded were studies that did not report on at least one of the above-mentioned items.

Results A total of 103 studies, the results of which contained at least 1 of the prespecified outcome variables, were identified. These studies reported 130 patient groups comprising 8949 patients. There were 3 prospective randomized studies, 1 prospective nonrandomized alternating study, 15 prospective nonrandomized data collections, and 84 retrospective reviews. The review revealed a trend for the use of miniplates or hydroxyapatite spacers on the open side in Hirabayashi-type laminoplasty or on the open side in a Kurokawa-type laminoplasty. Japanese Orthopaedic Association (JOA) scoring was reported most commonly; in the 4949 patients for whom a JOA score was reported, there was improvement from a mean (± SD) score of 9.91 (± 1.65) to a score of 13.68 (± 1.05) after a mean follow-up of 44.18 months (± 35.1 months). The mean preoperative and postoperative C2–7 angles (available for 2470 patients) remained stable from 14.17° (± 0.19°) to 13.98° (± 0.19°) of lordosis (average follow-up 39 months). The authors found significantly decreased kyphosis when muscle/posterior element–sparing techniques were used (p = 0.02). The use of hardware in the form of hydroxyapatite spacers or miniplates did not influence the progression of deformity (p = 0.889). An overall mean (calculated from 2390 patients) of 47.3% loss of range of motion was reported. For the studies that used a visual analog scale score (totaling 986 patients), the mean (cohort size–adjusted) postoperative pain level at a mean follow-up of 29 months was 2.78. For the studies that used percentages of patients who complained of postoperative axial neck pain (totaling 1249 patients), the mean patient number–adjusted percentage was 30% at a mean follow-up of 51 months. The authors found that 16% of the studies that were published in the last 10 years reported a C-5 palsy rate of more than 10% (534 patients), 41% of the studies reported a rate of 5%–10% (n = 1006), 23% of the studies reported a rate of 1%–5% (n = 857), and 12.5% reported a rate of 0% (n = 168).

Conclusions Laminoplasty remains a valid option for decompression of the spinal cord. An understanding of the importance of the muscle-ligament complex, plus the introduction of hardware, has led to progress in this type of surgery. Reporting of outcome metrics remains variable, which makes comparisons among the techniques difficult.

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Distraction, Compression, Extension, and Reduction Combined With Joint Remodeling and Extra-articular Distraction: Description of 2 New Modifications for Its Application in Basilar Invagination and Atlantoaxial Dislocation: Prospective Study in 79 Cases

Distraction,_Compression,_Extension,_and_Reduction

Neurosurgery 77:67–80, 2015

Recent strategies for treatment of basilar invagination (BI) and atlantoaxial dislocation (AAD) are based on simultaneous posterior reduction and fixation.

OBJECTIVE: To describe new modifications of the procedure distraction, compression, extension, and reduction (DCER), ie, joint remodeling (JRM) and extra-articular distraction (EAD) in patients with “vertical” joints, and to quantify the improvement in joint indices, ie, sagittal inclination (SI), craniocervical tilt (CCT), and coronal inclination.

METHODS: Prospective study (May 2010 to September 2014). Joint indices measured included (normal values): SI (87.15 ± 5.65º), CCT (60.2 ± 9.2), and coronal inclination (110.3 ± 4.23). Surgical procedures included DCER alone (performed in SI ,100, group I) or JRM with DCER (in SI: 100-160, group II), or EAD with DCER in severe BI with almost vertical joints (SI >160º, group III).

RESULTS: Seventy-nine patients were selected (mean, 22.5 years of age). All conventional indices improved significantly (P < .001). CCT improved in all groups (P < .01); group I (n = 32): 54 ± 8.7 (preoperative 80.71 ± 12.72); group II (n = 40): 58 ± 7.0 (preoperative 86.5 6 14); group III (n = 7): 62 ± 10.0 (preoperative 104 6 11.2). SI improved in both group I and II, P < .01 (cannot be measured in group III). At long-term follow-up (n = 64, 29 ± 8 months, range 12-39 months), the Nurick grade improved to 1.5 ±0.52 (preoperative: 3.4 6 0.65; P < .001).

CONCLUSION: DCER seems to be an effective technique in reducing both BI and AAD. JRM and EAD with DCER are useful in moderate to severe BI and AAD (with SI .100). Joint indices provide useful information for surgical strategy and planning.

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Three-Dimensional Computed Tomography-Based Spinal Navigation in Minimally Invasive Lateral Lumbar Interbody Fusion

Three-Dimensional Computed Tomography-Based Spinal Navigation in Minimally Invasive Lateral Lumbar Interbody Fusion4

Operative Neurosurgery 11:259–267, 2015

As with most minimally invasive spine procedures, lateral lumbar interbody fusion (LLIF) requires the use of biplanar fluoroscopy for localization and safe interbody cage placement. Computed tomography (CT)-based intraoperative spinal navigation has been shown to be more effective than fluoroscopic guidance for posterior-based approaches such as pedicle screw instrumentation. However, the use of spinal navigation in LLIF has not been well studied.

OBJECTIVE: To present the technique for using an intraoperative cone-beam CT and image-guided navigation system in LLIF and to provide a preliminary analysis of outcomes.

METHODS: We retrospectively analyzed a prospectively acquired database and the electronic records of patients undergoing LLIF with spinal navigation. Eight patients were identified. Postoperative neurological deficits were recorded. All patients underwent postprocedural CT and x-ray imaging for analysis of accuracy of cage placement. Accuracy of cage placement was determined by location within the disk space.

RESULTS: The mean age was 66 years, and 6 patients were women. A mean 2.8 levels were treated with a total of 22 lateral cages implanted via navigation. All cages were placed within quarters 1 to 2 or 2 to 3, signifying the anterior half or middle portions of the disk space. There were no sensory or motor deficits postoperatively.

CONCLUSION: Use of an intraoperative cone-beam CT with an image-guided navigation system is feasible and safe and appears to be accurate, although a larger study is required to confirm these results.

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Long-term Outcomes of the US FDA IDE Prospective, Randomized Controlled Clinical Trial Comparing PCM Cervical Disc Arthroplasty With Anterior Cervical Discectomy and Fusion”

PCM vs ACDF

Spine 2015;40:674–683

Study Design. Prospective, multicenter, randomized clinical trial.

Objective. To evaluate the long-term safety and effectiveness of the PCM Cervical Disc compared with anterior cervical discectomy and fusion (ACDF) in treatment of patients with symptomatic single- level degenerative spondylosis between C3–C4 and C7–T1 with or without prior cervical fusion.

Summary of Background Data. The 2-year results of the PCM Cervical Disc trial have been reported previously. The current study reports the long-term results of the same trial.

Methods. Patients with single-level cervical spondylosis and radiculopathy with or without myelopathy unresponsive to nonoperative treatment were enrolled. The per protocol patient sample at 5 years included 293 patients (163 PCM, 130 ACDF). Adverse events and secondary surgical procedures are reported on the cohorts through current follow-up, which include 110 patients (68 PCM, 42 ACDF) at 7 years.

Results. At 5 years postoperative, all patient-reported outcomes— neck and arm pain visual analogue scale score, neck disability index, and general health (36-Item Short Form Health Survey physical and mental component scores: physical component summary, mental component summary)—were significantly improved from baselines in both groups, and mean scores were significantly better in the PCM group for neck disability index (P = 0.001), neck pain (P = 0.002), general health (Pphysical component summary= 0.014; P mental component summary= 0.004), and patient satisfaction (P = 0.005).
PCM patients trended toward fewer 2- to 7-year device-related
serious adverse events (1/214, 0.5% PCM; 2/190, 1.1% ACDF) and secondary surgical procedures (7/211, 3.3% PCM; 14/290, 7.6% ACDF). Adjacent-level degeneration was radiographically more frequent after ACDF (33.1% PCM, 50.9% ACDF; P = 0.006) and was the primary indication for the increase in late-term secondary surgical procedures after ACDF.

Conclusion. The long-term results show good clinical outcomes after ACDF and PCM arthroplasty. PCM patients showed greater improvement in neck disability index and neck pain scores with a lower rate of radiographical adjacent-level degeneration and a trend toward fewer secondary surgical procedures. These data support PCM arthroplasty to be a viable and sustainable alternative to ACDF.
Level of Evidence: 1

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Adjacent Segment Pathology Requiring Reoperation After Anterior Cervical Arthrodesis

Outcomes After Anterior Cervical Discectomy and Fusion in Professional AthletesSpine 2015;40:E571–E577

Study Design. A retrospective study.

Objective. The purpose of this study was to determine, using survivorship analysis, the rate of adjacent segment pathology (ASP) development and to identify the risk factors for reoperation.

Summary of Background Data. The study of Hilibrand defi ned “adjacent segment disease” as symptomatic radiculopathy or myelopathy due to an adjacent segment documented on 2 consecutive offi ce visits. In addition to being somewhat subjective, their criterion is not as practical as identifying the rate of adjacent pathology by the need for reoperation.

Methods. This was a retrospective analysis of 1038 consecutive patients who underwent primary anterior cervical spine arthrodesis for radiculopathy and/or myelopathy by 1 surgeon. Annual incidence and prevalence of ASP requiring surgery were calculated and survivorship was determined. We used the Cox regression for risk factor analysis.

Results. Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.4% per year (95% confi dence interval, 1.9–3.0). The Kaplan-Meier analysis predicted that 22.2% of patients would need reoperation at adjacent segments by 10 years postoperatively. Factors increasing the risk were smoking, female sex, and the number of arthrodesis segments. One or 2-segment arthrodesis had an 1.8 times greater risk than arthrodesis involving 3 or more segments. Age, neurological diagnosis, diabetes, Klippel- Feil syndrome, and noncontiguous segmental-type ossifi cation of posterior longitudinal ligament were not signifi cant risks.

Conclusion. Patients treated with 1- or 2-segment anterior cervical arthrodesis are more likely to develop ASP than those treated with arthrodesis involving 3 or more segments. Smokers and women had a higher ASP reoperation rate. Our series, the largest in the literature, predicts that 22.2% of patients will require reoperation for ASP within 10 years, substantially higher than the Hilibrand study.

Level of Evidence: 3

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