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Background: Assessing the impact of spine disorders such as lumbar degenerative spondylolisthesis (LDS) on overall health is a component of quality of care that may not be comprehensively captured by spine-specific and single-attribute patient-reported outcome measures (PROMs). Purpose: We sought to compare PROMs to the Lumbar Surgery Expectations Survey (“Expectations Survey”), which addresses multiple aspects of health and well-being, and to compare the relevance of surgeon-selected versus survey-selected Patient-Reported Outcomes Measurement Information System (PROMIS) items to LDS. Methods: In a cross-sectional study, 379 patients with LDS preoperatively completed the Expectations Survey, Numerical Rating Pain Scales, Oswestry Disability Index (ODI), and PROMIS computer-adaptive physical function, pain, and mental health surveys. Expectations Survey scores were compared to PROMs with correlation coefficients (indicating strengths of relationships) and probability values (indicating associations by chance). Surgeons reviewed physical function questions to identify those particularly relevant to LDS. Results: Patients’ mean age was 67 years, 64% were women, and 83% had single-level and 17% had multiple-level LDS. Probability values between the Expectations Survey and PROMs were reliable, but strengths of relationships were only mild to moderate, indicating PROMs did not comprehensively capture the impact of LDS. None of the surgeon-selected PROMIS physical function questions were posed to patients. Conclusion: This cross-sectional study found PROMs to be reliably associated but not strongly correlated with the Expectations Survey, which addresses the whole-patient impact of LDS. New measures that complement PROMIS and ODI should be developed to capture the whole-person effects of LDS and permit attribution of LDS treatments to overall health.

Background: Quantitative computed tomography (qCT) efficiently measures 3-dimensional vertebral bone mineral density (BMD), but its utility in measuring BMD at various vertebral levels in patients with lumbar degenerative spondylolisthesis (LDS) is unclear. Purpose: We sought to determine whether qCT could differentiate BMD at different levels of LDS, particularly at L4-L5, the most common single level for LDS. In addition, we sought to describe patterns of BMD for single-level and multiple-level LDS. Methods: We conducted a study of patients undergoing surgery for LDS who were part of a larger longitudinal study comparing preoperative and intraoperative images. Preoperative patients were grouped as single-level or multiple-level LDS, and qCT BMD was obtained for L1-S1 vertebrae. Mean BMD was compared with literature reports; in multivariable analyses, BMD of each vertebra was assessed according to the level of LDS, controlling for covariates and for BMD of other vertebrae. Results: Of 250 patients (mean age: 67 years, 64% women), 22 had LDS at L3-L4 only, 170 at L4-L5 only, 13 at L5-S1 only, and 45 at multiple levels. Compared with other disorders reported in the literature, BMD in our sample similarly decreased from L1 to L3 then increased from L4 to S1, but mean BMD per vertebra in our sample was lower. Nearly half of our sample met criteria for osteopenia. In multivariable analysis controlling for BMD at other vertebrae, lower L4 BMD was associated with LDS at L4-L5, greater pelvic incidence minus lumbar lordosis, and not having diabetes. In contrast, in similar multivariable analysis, greater L4 BMD was associated with LDS at L3-L4. Bone mineral density of L3 and L5 was not associated with LDS levels. Conclusion: In our sample of preoperative patients with LDS, we observed lower BMD for LDS than for other lumbar disorders. L4 BMD varied according to the level of LDS after controlling for covariates and BMD of other vertebrae. Given that BMD can be obtained from routine imaging, our findings suggest that qCT data may be useful in the comprehensive assessment of and strategy for LDS surgery. More research is needed to elucidate the cause-effect relationships among spinopelvic alignment, LDS, and BMD.

As robotics in spine surgery has progressed over the past 2 decades, studies have shown mixed results on its clinical outcomes and economic impact. In this review, we highlight the evolution of robotic technology over the past 30 years, discussing early limitations and failures. We provide an overview of the history and evolution of currently available spinal robotic platforms and compare and contrast the available features of each. We conclude by summarizing the literature on robotic instrumentation accuracy in pedicle screw placement and clinical outcomes such as complication rates and briefly discuss the future of robotic spine surgery.

Background K-wireless robotic pedicle screw instrumentation with navigation is a new technology with large potential. Barriers to adoption are added registration time with robotic-navigated system and reliable screw positioning. Understanding the learning curve and limitations is crucial for successful implementation. The purpose of this study was to describe a learning curve of k-wireless robotic assisted pedicle screw placement with navigation and compare to conventional techniques. Methods A retrospective review of prospectively collected data of 65 consecutive adult patients underwent robotic-navigated posterior spinal fusion by a single spine surgeon. Registration, screw placement, and positioning times were recorded. All patients underwent intra-operative 3D fluoroscopy and screw trajectory was compared to pre-operative CT. Results A total of 364 instrumented pedicles were planned robotically, 311 (85.4%) were placed robotically; 17 screws (4.7%) converted to k-wire, 21 (5.8%) converted to freehand, and 15 (4.1%) planned freehand. Of the 311 robotically placed pedicle screws, three dimensional fluoroscopic imaging showed 291 (93.5%) to be GRS Grade A in the axial plane (fully contained within the pedicle) and 281 (90.4%) were GRS Grade A in the sagittal plane. All breached screw deviations from plan were identified on 3D fluoroscopy during surgery and repositioned and confirmed by additional 3d fluoroscopy scan. Reasons for conversion included morphology of starting point (n=18), soft tissue pressure (n=9), hypoplastic pedicles (n=6), obstructive reference pin placement (n=2), and robotic arm issues (n=1). Seventeen (5.5%) critical breaches (≥2-4 mm) were recorded in 11 patients, 9 (2.9%) critical breaches were due to soft tissue pressure causing skive. Two patients experienced 6 (1.9%) critical breaches from hypoplastic pedicles, and 3 (0.9%) unplanned lateral breaches were found in another patient. One patient (0.3%) experienced skive due to morphology and spinal instability from isthmic spondylolisthesis. Imaging showed 143 screws placed medially to plan (1.2±0.9 mm), 170 lateral (1.2±1.1 mm), 193 screws caudal (1.0±0.6 mm) and 117 cranial (0.6±0.5 mm). No adverse clinical sequelae occurred from implantation of any screw. Conclusions The learning curve showed improvement in screw times for the first several cases. Understanding the learning curve and situations where the robotic technique may be suboptimal can help guide the surgeon safe and effectively for adoption, as well as further refine these technologies.

Study Design Medical vignettes. Objectives Lumbar spinal stenosis (LSS) is a degenerative condition with a high prevalence in the elderly population, that is associated with a significant economic burden and often requires spinal surgery. Prior authorization of surgical candidates is required before patients can be covered by a health plan and must be approved by medical directors (MDs), which is often subjective and clinician specific. In this study, we hypothesized that the prediction accuracy of machine learning (ML) methods regarding surgical candidates is comparable to that of a panel of MDs. Methods Based on patient demographic factors, previous therapeutic history, symptoms and physical examinations and imaging findings, we propose an ML which computes the probability of spinal surgical recommendations for LSS. The model implements a random forest model trained from medical vignette data reviewed by MDs. Sets of 400 and 100 medical vignettes reviewed by MDs were used for training and testing. Results The predictive accuracy of the machine learning model was with a root mean square error (RMSE) between model predictions and ground truth of .1123, while the average RMSE between individual MD’s recommendations and ground truth was .2661. For binary classification, the AUROC and Cohen’s kappa were .959 and .801, while the corresponding average metrics based on individual MD’s recommendations were .844 and .564, respectively. Conclusions Our results suggest that ML can be used to automate prior authorization approval of surgery for LSS with performance comparable to a panel of MDs.

Summary: Background: Lumbar intervertebral disc (IVD) herniations are associated with significant disability. Discectomy is the conventional treatment option for IVD herniations but causes a defect in the IVD, which has low self-repair ability, thereby representing a risk of further IVD degeneration. An acellular, bioresorbable, and good manufacturing practice (GMP)-compliant in situ-forming gel, which corrects discectomy-associated IVD defects and prevents further IVD degeneration had been developed. However, this acellular matrix-based strategy has certain limitations, particularly in elderly patients, whose tissues have low self-repair ability. The aim of this study was to investigate the therapeutic efficacy of using a combination of newly-developed, ultra-purified, GMP-compliant, human bone marrow mesenchymal stem cells (rapidly expanding clones; RECs) and the gel for IVD regeneration after discectomy in a sheep model of severe IVD degeneration. Methods: RECs and nucleus pulposus cells (NPCs) were co-cultured in the gel. In addition, RECs combined with the gel were implanted into IVDs following discectomy in sheep with degenerated IVDs. Findings: Gene expression of NPC markers, growth factors, and extracellular matrix increased significantly in the co-culture compared to that in each mono-culture. The REC and gel combination enhanced IVD regeneration after discectomy (up to 24 weeks) in the severe IVD degeneration sheep model. Interpretation: These findings demonstrate the translational potential of the combination of RECs with an in situ-forming gel for the treatment of herniations in degenerative human IVDs. Funding: Ministry of Education, Culture, Sports, Science, and Technology of Japan, Japan Agency for Medical Research and Development, and the Mochida Pharmaceutical Co., Ltd.

Background: Three-dimensional (3D) computer-assisted navigation (CAN) has emerged as a potential alternative to 2-dimensional (2D) fluoroscopy in the surgical placement of spinal instrumentation. Recently, 3D-CAN systems have improved significantly in their ability to provide real-time anatomical referencing while shortening the registration and set-up time. A novel system in navigation, Machine-Vision Image-Guided Surgery (MvIGS; 7D Surgical, Toronto, Canada) was cleared by the US Food and Drug Administration, but its potential benefits in reducing intra-operative radiation exposure to patients and enhancing surgical accuracy of pedicle screw placement are not fully known. Purpose: We sought to conduct a prospective, randomized, clinical study comparing the 3D-MvIGS spinal navigation system and 2D-fluoroscopy for pedicle screw insertion up to 3 levels (T10-S1) and for various measures of surgical efficacy. Methods: Sixty-two eligible patients were randomized to receive spine surgery using either the 3D-MvIGS group or the conventional 2D-fluoroscopy for pedicle screw fixation for the treatment of spinal stenosis and degenerative spondylolisthesis. Intra-operative parameters and procedure-related unintended protocol violations were recorded. Results: Operative time and estimated blood loss were not significantly different between groups. Radiation time and exposure to patients were significantly reduced in the 3D-MvIGS group. There was no difference between groups in pedicle screw placement accuracy (2D-fluoroscopy group, 96.6%; 3D-MvIGS group, 94.2%). There were no major complications or cases that required revision surgery. Conclusion: The 3D-MvIGS navigation system performed comparably with 2D-fluoroscopy in terms of pedicle screw placement accuracy and operative time. The 3D-MvIGS showed a significant reduction in radiation exposure to patients. In more complex cases or larger cohorts, the true value of greater anatomical visualization can be elucidated.

Background: Robotic-assisted and computer-assisted navigation (CAN) systems utilization has been rapidly increasing in recent years. Most existing data using these systems are performed in the thoracic, lumbar, and sacral spine. The unique anatomy of the cervical spine maybe where these technologies have the greatest potential. To date, the role of navigation-enabled robotics in the cervical spine remains in its early stages of development and study. Purpose: This review article describes the early experience, case descriptions and technical considerations with cervical spine screw fixation and decompression using CAN and robotic-assisted surgery. Methods: Representative cervical cases with early surgical experience with cervical and robotic assisted surgery with CAN. Surgical set up, technique considerations, instrumentation, screw accuracy and screw placement were elevated and recorded for each representative cervical case. Results: Existing robotic assisted spine surgical systems are reviewed as they pertain to the cervical spine. Method for cervical reference and positioning on radiolucent Mayfield tongs are presented. C1 lateral mass, odontoid fracture fixation, C2 pedicle, translaminar, subaxial lateral mass, mid cervical pedicle, navigated decompression and ACDF cases and techniques are presented. Conclusion: In conclusion, within the last several years, the use of CANs in spinal surgery has grown and the cervical spine shows the greatest potential. Several robotic systems have had FDA clearance for use in the spine, but such use requires simultaneous intraoperative fluoroscopic confirmation. In the coming years, this recommendation will likely be dropped as accuracy improves.

Study Design: Retrospective case series. Objective: To report contemporary rates of complications and subsequent surgery after spinal surgery in patients with skeletal dysplasia. Methods: A case series of 25 consecutive patients who underwent spinal surgery between 2007 and 2017 were identified from a single institution’s skeletal dysplasia registry. Patient demographics, medical history, surgical indication, complications, and subsequent surgeries (revisions, extension to adjacent levels, or for pathology at a non-contiguous level) were collected. Charlson comorbidity indices were calculated as a composite measure of overall health. Results: Achondroplasia was the most common skeletal dysplasia (76%) followed by spondyloepiphyseal dysplasia (20%); 1 patient had diastrophic dysplasia (4%). Average patient age was 53.2 ± 14.7 years and most patients were in excellent cardiovascular health (88% Charlson Comorbidity Index 0-4). Mean follow up after the index procedure was 57.4 ± 39.2 months (range). Indications for surgery were mostly for neurologic symptoms. The most commonly performed surgery was a multilevel thoracolumbar decompression without fusion (57%). Complications included durotomy (36%), neurologic complication (12%), and infection requiring irrigation and debridement (8%). Nine patients (36%) underwent a subsequent surgery. Three patients (12%) underwent a procedure at a non-contiguous anatomic zone, 3 (12%) underwent a revision of the previous surgery, and another 3 (12%) required extension of their previous decompression or fusion. Conclusions: Surgical complication rates remain high after spine surgery in patients with skeletal dysplasia, likely attributable to inherent characteristics of the disease. Patients should be counseled on their risk for complication and subsequent surgery.

Study Design: Narrative review. Objectives: The etiology of adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDz) after lumbar interbody fusion (LIF) remains controversial. The aim of this narrative review was to provide an evidence-based analysis of the peer-reviewed literature on clinical studies of ASDeg and ASDz after LIF. Methods: A review was performed utilizing Medline, Embase, and Cochrane databases. Two reviewers independently extracted relevant data from each included study. Statistical comparisons were made when appropriate. Results: Nine articles that matched the inclusion and exclusion criteria were included. All the studies were Level III and retrospective. MINORS scores ranged from 9.5 to 13. Clinical outcomes were assessed in all 9 studies, but only 6 studies used validated outcomes measures. Only 6 studies reported values for both ASDeg and ASDz. ASDeg alone was reported in 3 studies. Due to the variability in the criteria for designation as ASDz (different radiographic modalities) and ASDeg (different outcomes measures), we were unable to calculate frequency-weighted mean values or compare the various surgical techniques. Conclusions: This review highlights the various limitations of the current literature on ASDeg and ASDz after lumbar fusion, specifically the absence of a rigorous definition and classification system and an extraordinary heterogeneity in methodology. There needs to be a fundamental shift in the current ASDeg and ASDz research landscape, toward a consensus, so that the high-level clinical research that is essential for treatment of spinal pathology may become available.

The sequelae of atlantoaxial instability (AAI) range from axial neck pain to life-threatening neurologic injury. Instrumentation and fusion of the C1-2 joint is often indicated in the setting of clinical or biomechanical instability. This is the first clinical report of anterior Smith-Robinson C1-2 transarticular screw (TAS) fixation for AAI. The first patient presented with ischemic brain tissue secondary to post-traumatic C1-2 segment instability from a MVC 7 years prior to presentation. The second patient presented with a 3 year history of persistent right-sided neck and upper scalp pain. Both were treated with transarticular C1-2 fusion through decortication of the atlantoaxial facet joints and TAS fixation via the anterior Smith-Robinson approach. At 16 months follow-up, the first patient maintained painless range of motion of the cervical spine and denied sensorimotor deficits. The second patient reported 90% improvement in her pre-operative symptoms of neck pain and paresthesia. Anterior Smith-Robinson C1-2 TAS fixation provides a useful alternative to the posterior Goel and Magerl techniques for C1-2 stabilization and fusion.

Age-related changes in the spinal column result in a degenerative cascade known as spondylosis. Genetic, environmental, and occupational influences may play a role. These spondylotic changes may result in direct compressive and ischemic dysfunction of the spinal cord known as cervical spondylotic myelopathy (CSM). Both static and dynamic factors contribute to the pathogenesis. CSM may present as subclinical stenosis or may follow a more pernicious and progressive course. Most reports of the natural history of CSM involve periods of quiescent disease with intermittent episodes of neurologic decline. If conservative treatment is chosen for mild CSM, close clinical and radiographic follow-up should be undertaken in addition to precautions for trauma-related neurologic sequelae. Operative treatment remains the standard of care for moderate to severe CSM and is most effective in preventing the progression of disease. Anterior surgery is often beneficial in patients with stenotic disease limited to a few segments or in cases in which correction of a kyphotic deformity is desired. Posterior procedures allow decompression of multiple segments simultaneously provided that adequate posterior drift of the cord is attainable from areas of anterior compression. Distinct risks exist with both anterior and posterior surgery and should be considered in clinical decision-making.

Early detection of surgical site infection (SSI) following spinal surgery would allow for prompt treatment and would improve overall outcome, yet early diagnosis is a challenge. Computed tomography (CT) guided aspiration of fluid collections may aid in diagnosis, as its diagnostic utility has previously been demonstrated in the setting of hip SSI, knee SSI, and spontaneous diskitis. There is no literature on its use in post-operative spinal SSIs.The current study aims to (1) determine the diagnostic value of CT-guided aspiration in evaluating suspected SSI; (2) identify the characteristics of the clinical presentation that are predictive of SSI; and (3) identify characteristics of the hematologic workup that are predictive of SSI.Thirty patients who underwent CT-guided aspiration of paraspinal post-operative fluid collections and culture of aspirate fluid over the 6-year period from 2006 to 2011 were retrospectively reviewed. Aspirate fluid culture results were compared to intraoperative cultures, which were used as the "gold standard" for diagnosing SSI. The diagnostic value was evaluated by determining the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of aspirate fluid cultures. Clinical presentation, patient demographics, comorbidities, and laboratory values were reviewed for association with infection risk.Eleven of thirty patients undergoing CT-guided aspiration were subsequently confirmed to have SSI through positive cultures. Wound drainage, wound erythema, elevated ESR, and cloudiness of aspirate fluid were associated with SSI. The sensitivity and specificity of aspirate cultures were 36.4 and 89.5%, respectively, and the respective positive predictive value (PPV) and negative predictive value (NPV) were 66.7 and 70.8%.Cloudy aspirate fluid was highly suggestive of infection, while wound erythema, drainage, and elevated ESR were also suggestive of SSI. CT-guided aspirations are a useful adjunct tool in evaluating for SSI but further studies are necessary before it can be considered a stand-alone diagnostic procedure.

Background— Growth factors play an essential role in organogenesis. We examine the potential of growth factors to enhance cell engraftment and differentiation and to promote functional improvement after transfer of undifferentiated embryonic stem cells into the injured heart. Methods and Results— Green fluorescent protein (GFP)–positive embryonic stem cells derived from 129sv mice were injected into the ischemic area after left anterior descending artery ligation in allogenic (BALB/c) mice. Fifty nanograms of recombinant mouse vascular endothelial growth factor, fibroblast growth factor (FGF), and transforming growth factor (TGF) was added to the cell suspension. Separate control groups were formed in which only the growth factors were given. Echocardiography was performed 2 weeks later to evaluate heart function (fractional shortening [FS]), end-diastolic diameter, and left ventricular wall thickness). Hearts were harvested for histology (connexin 43, α-sarcomeric actin, CD3, CD11c, major histocompatability complex class I, hematoxylin-eosin). Degree of restoration (GFP-positive graft/infarct area ratio), expression of cardiac markers, host response, and tumorigenicity were evaluated. Cell transfer resulted in improved cardiac function. TGF-β led to better restorative effect and a stronger expression of connexin 43, α-sarcomeric actin, and major histocompatability complex class I. TGF-β and FGF retained left ventricular diameter. FS was better in the TGF-β, FGF, and embryonic stem cells-only group compared with left anterior descending artery-ligated controls. Growth factors with cells (TGF-β, FGF) resulted in higher FS and smaller end-diastolic diameter than growth factors alone. Conclusions— Growth factors can promote in vivo organ-specific differentiation of early embryonic stem cells and improve myocardial function after cell transfer into an area of ischemic lesion. TGF-β should be considered as an adjuvant for myocardial restoration with the use of embryonic stem cells.

Insulin-like growth factor-1 (IGF-1) promotes myocyte proliferation and can reverse cardiac abnormalities when it is administered in the early fetal stage. Supplementation of a mouse embryonic stem cell (ESC) suspension with IGF-1 might enhance cellular engraftment and host organ-specific differentiation after injection in the area of acute myocardial injury. In the study reported here, we sought to enhance the restorative effect of ESCs in the injured heart by adding IGF-1 to the injected cell population. Green fluorescent protein (GFP)-labeled sv129 ESCs (2.5 x 10(5)) were injected into the ischemic area after left anterior descending (LAD) artery ligation in BalbC mice. Recombinant mouse IGF-1 (25 ng) was added to the cell suspension prior to the injection (n = 5). Echocardiography was performed before organ harvest 2 weeks later. The degree of restoration (ratio of GFP+ to infarct area), expression of cardiac markers by GFP+ cells, inflammatory response, and tumorigenicity were evaluated. Mice with LAD ligation only (n = 5) and ESC transfer without IGF-1 (n = 5) served as controls. ESCs formed viable grafts and improved cardiac function. Left ventricular wall thickness was higher in the IGF-1 group (p = .025). There was a trend toward higher fractional shortening in the IGF-treated group. Histological analysis demonstrated that IGF-1 promoted expression of alpha-sarcomeric actin (p = .015) and major histocompatibility complex class I (p = .01). IGF did not affect the cellular response to the donor cells or tumorigenicity. IGF-1 promotes expression of cardiomyocyte phenotype in ESCs in vivo. It should be considered as an adjuvant to cell transfer for myocardial restoration.

ObjectivesMost tissue-engineering approaches to restore injured heart muscle result in distortion of left ventricular geometry. In the present study we suggest seeding embryonic stem cells in a liquid matrix for myocardial restoration.MethodsUndifferentiated green fluorescent protein–labeled mouse embryonic stem cells (2 × 106) were seeded in Matrigel (B&D, Bedford, Mass). In a Lewis rat heterotopic heart transplant model an intramural left ventricular pouch was fashioned after ligation of the left anterior descending coronary artery. The liquid mixture (0.125 mL) was injected in the resulting infarcted area within the pouch and solidified within a few minutes after transplantation (37°C). Five recipient groups were formed: transplanted healthy hearts (group I), infarcted control hearts (group II), matrix recipients alone (group III), the study group that received matrix plus cells (group IV), and a group that received embryonic stem cells alone (group V). After echocardiography 2 weeks later, the hearts were harvested and stained for green fluorescent protein and cardiac muscle markers (connexin 43 and α-sarcomeric actin).ResultsThe graft formed a sustained structure within the injured area and prevented ventricular wall thinning. The inoculated cells remained viable and expressed connexin 43 and α-sarcomeric actin. Fractional shortening and regional contractility were better in animals that received bioartificial tissue grafts compared with control animals (infarcted, matrix only, and embryonic stem cells only: group I, 17.0% ± 3.5%; group II, 6.6% ± 2.1%; group III, 10.3% ± 2.2%; group IV, 14.5% ± 2.5%; and group V, 7.8% ± 1.8%).ConclusionsLiquid bioartificial tissue containing embryonic stem cells constitutes a powerful new approach to restoring injured heart muscle without distorting its geometry and structure.

Cervical spondylotic myelopathy (CSM) is a common indication for cervical spine surgery. Surgical options include anterior, posterior, or combined procedures each with specific advantages and disadvantages.This article will provide a description of the various anterior alternatives and discuss the available evidence used in guiding the surgical decision making process with the aim of answering the following questions: (1) What anatomical/disease related factors favor anterior over posterior surgeries? (2) What are the common anterior procedures and how safe and effective are they? (3) What are the most effective options for multilevel CSM? (4) Is there a role for motion preservation? An additional objective is to discuss technical advances that have improved success rates for anterior procedures.The PubMed database was searched. Keywords were CSM and anterior surgery. Three hundred eighty two articles were found one hundred three were reviewed. Articles describing anterior cervical techniques were selected along with studies describing the various anterior techniques or comparisons of anterior to posterior techniques.Anterior decompression and fusion procedures are more effective than posterior procedures for patients with primarily ventrally located compression especially in the presence of cervical kyphosis. ACDF, ACCF, and hybrid combinations are safe and effective treatment options for multilevel CSM. Anterior procedures may be more cost effective and result in significantly improved postoperative quality of life and health-related quality of life measures compared to posterior procedures.Anterior cervical decompression techniques are safe and effective in the treatment of CSM. Anterior surgeries may be preferable to posterior approaches, when considering health-related quality of life measures and cost effectiveness.

Anterior cervical discectomy and fusion (ACDF) is widely accepted as a predictably excellent procedure. On the other hand, adjacent level pathology following ACDF is a well-known phenomenon which undercuts surgical outcome. However, the extent to which ACDF accelerates this phenomenon in the naturally degenerating cervical spine is still to be understood.To summarize the current evidence concerning adjacent segment pathology in the light of biomechanics, natural history, postoperative course, and comparison between ACDF and total disc replacement (TDR).This is a study of published articles. Articles were searched by the topic of adjacent disc pathology in cervical spine through Google Scholar and Pubmed. After review, 37 published articles were deemed suitable for the subject of this study.Biomechanical and clinical data strongly suggest that ASP is a presentation of the iatrogenically accelerated natural aging process of cervical spine. However, power study analysis with assumption showed that current RCTs are unlikely to prove this suggestion.Available data suggests that iatrogenic factors play a significant role in adjacent segment pathology following ACDF.

Cervical spondylosis is now recognised as the leading cause of myelopathy and spinal cord dysfunction worldwide. Chronic spinal cord compression results in chronic inflammation, cellular apoptosis, and microvacular insufficiency, which are thought to the biologic basis for cervical spondylotic myelopathy (CSM).Our purpose was to address the key principles of CSM, including natural history and presentation, pathogenesis, optimal surgical approach, results and complication rates of posterior surgical approaches for CSM so that the rationale for addressing CSM by a posterior approach can be fully understood.We conducted a systematic search of PubMed/MEDLINE and the Cochrane Collaboration Library for literature published through February 2014 to identify articles that evaluated CSM and its management. Reasons for exclusion included patients with ossification of the posterior longitudinal ligament (OPLL), patients with degenerative disc disease without CSM, and patients with spine tumor, trauma and infection. Meeting abstracts/proceedings, white articles and editorials were additionally excluded.The search strategy yielded 1,292 articles, which was reduced to 52 articles, after our exclusion criteria were introduced. CSM is considered to be a surgical disorder due to its progressive nature. There is currently no consensus in the literature whether multilevel spondylotic compression is best treated via an anterior or posterior surgical approach.Multilevel CSM may be safely and effectively treated using a posterior approach, either by laminoplasty or with a laminectomy and fusion technique.

Design Retrospective case series. Objective The objective of this study was to assess the reoperation rate after microdiscectomy for the treatment of lumbar disc herniation (LDH) in patients with ≥ 5-year follow-up and identify demographic, perioperative, and outcome-related differences between patients with and without a reoperation. Methods The medical records, operative reports, and office notes of patients who had undergone microdiscectomy at a single institution between March 1994 and December 2007 were reviewed and long-term follow-up was assessed via a telephone questionnaire. Results Forty patients (M:24, F:16) with an average age at surgery of 39.9 ± 12.5 years (range: 18–80) underwent microdiscectomy at the levels L5–S1 (n = 28, 70%), L4-L5 (n = 9, 22.5%), L3–L4 (n = 2, 5.0%), and L1–L2 (n = 1, 2.5%). After an average of 40.4 ± 40.1 months (range: 1–128), 25% of patients (10/40) required further spine surgery related to the initial microdiscectomy. At an average postoperative follow-up of 11.1 ± 4.0 years (range: 5–19), additional symptoms apart from back and leg pain were reported more frequently by patients who underwent a reoperation (p = 0.005). Patient satisfaction was significantly higher in patients who did not undergo a reoperation (p = 0.041). For the Oswestry disability index, pain intensity (p = 0.036), and pain-related sleep disturbances (p = 0.006) were reported to be more severe in the reoperation group. Conclusions Microdiscectomy for the treatment of LDH results in a favorable long-term outcome in the majority of cases. The reoperation rate was higher in our series than reported in previous investigations with shorter follow-up. Although there were no statistically significant pre-/perioperative differences between patients with and without reoperation, our findings suggest a difference in self-reported long-term outcome measures.

Traumatic injury to the spinal cord can be divided into complete and incomplete subtypes, based on complete or partial absence of neurologic function below the level of injury. Incomplete spinal cord injury has been shown to occur following cervical hyperextension or flexion injury in the setting of preexisting cervical spinal stenosis. The broad spectrum of symptoms from incomplete spinal cord injury includes weakness and sensory deficits potentially affecting upper and lower extremities, as well as bowel, bladder, and sexual dysfunction in severe cases. The most common type of incomplete spinal cord injury is central cord syndrome, which is characterized by a more severely impaired motor function in the upper than the lower extremities [1, 8, 10, 13, 16]. Progressive neurological deficit has also been reported to occur due to C1–C2 pannus formation in the setting of rheumatic disease [4, 12, 17, 19, 20]. Crowned dens syndrome (CDS) is a rare but known cause of decreased cervical range of motion and severe axial neck pain, in the setting of calcium deposition around the odontoid, for which medical treatment with nonsteroidal anti-inflammatory drugs and/or steroids has been reported [2, 7]. Patients with CDS may present with symptoms of cervical myelopathy caused by a mass containing calcium pyrophosphate dihydrate (CPPD) at the atlantoaxial articulation and/or in the transverse ligament and/or in the ligamentum flavum [3, 9, 11, 14, 15]. According to the findings of Goto et al. evaluating 2,023 patients with neck pain as the chief complaint, 40 patients were identified with CDS, indicating a prevalence of 2.0% [7]. Chang et al. reported an overall prevalence of radiographically evident atlantoaxial CPPD deposition of 12.5%, which was increasing with age [5]. However, severe and gradually progressive neurological deterioration due to an isolated large mass consisting of calcium pyrophosphate at the C1–C2 level causing functional quadriplegia is rare, and, therefore, the optimal treatment remains to be determined. Surgical decompression and stabilization may alleviate the compression on the cervical spinal cord [11], yet the potential for neurological recovery remains to be further elucidated. We report the case of an 87-year-old male diagnosed with quadriplegia resulting from CDS who made an excellent recovery following surgical decompression.

To report three cases of transient perioperative neurological deficit in the absence of direct cord insult following decompression of the severely stenotic thoracic spine.The clinical and radiographic electronic medical records of three patients who underwent decompression for severe midthoracic stenosis with transient neurological deficits perioperatively were reviewed. The cases are presented with consideration of possible underlying mechanisms and multimodality intraoperative monitoring (IOM) findings.Two patients had neurologic changes on IOM and Stagnara wake-up test, the remaining patient had absent motor and sensory potentials at baseline and throughout the case. IOM changes were observed immediately following decompression in the absence of direct cord insult or displacement. Postoperatively all patients experienced neurological motor deficits which presented as complete paralysis of the right lower extremity in two of the patients and the left lower extremity in one patient. The deficit was transient-improvement of motor strength occurred between 1 and 13 months of follow-up in all patients.Decompression of a severely stenotic region of the thoracic spinal cord may lead to a complete yet transient motor deficit in the perioperative period in the absence of direct mechanical cord insult. Potential etiologies include ischemia-reperfusion injury, microthrombi, and altered perfusion due to internal recoil of spinal cord architecture following decompression. IOM may show conspicuous findings in such events, however, may not be relied upon when baseline potentials are sub-optimal. Recognition of this short-lived neurological deficit following decompression of the severely stenotic thoracic spine will improve preoperative patient counseling and merits further study for determination of the precise pathophysiology.

The advent of recombinant DNA technology has substantially increased the intra-operative utilization of biologic augmentation in spine surgery over the past several years after the Food and Drug Administration approval of the bone morphogenetic protein (BMP) class of molecules for indications in the lumbar spine. Much less is known about the potential benefits and risks of the "off-label" use of BMP in the cervical spine. The history and relevant literature pertaining to the use of the "off-label" implantation of the BMP class of molecules in the anterior or posterior cervical spine are reviewed and discussed. Early prospective studies of BMP-2 implantation in anterior cervical spine constructs showed encouraging results. Later retrospective studies reported potentially "life threatening complications" resulting in a 2007 public health advisory by the FDA. Limited data regarding BMP-7 in anterior cervical surgery was available with one group reporting a 2.4% early (< 30 d) complication rate (brachialgia and dysphagia). BMP use in the decompressed posterior cervical spine may result in neurologic or wound compromise according to several retrospective reports, however, controlled use has been reported to increase fusion rates in select complex and pediatric patients. There were no cases of de novo neoplasia related to BMP implantation in the cervical spine. BMP-2 use in anterior cervical spine surgery has been associated with a high early complication rate. Definitive recommendations for BMP-7 use in anterior cervical spine surgery cannot be made with current clinical data. According to limited reports, select complex patients who are considered "high risk" for pseudoarthrosis undergoing posterior cervical or occipitocervical arthrodesis or children with congenital or traumatic conditions may be candidates for "off-label" use of BMP in the context of appropriate informed decision making. At the present time, there are no high-level clinical studies on the outcomes and complication rates of BMP implantation in the cervical spine.

IntroductionPatients undergo lumbar spine surgery because they expect improvement in pain and function. Traditionally, pain outcomes have been measured with numerical scales that capture pain inten...

BackgroundPatients have multiple expectations of lumbar surgery and fulfillment of expectations is an important but infrequently studied outcome. The objective of this study was to compare patients...

IntroductionPatients have multiple expectations of cervical spine surgery that encompass physical and psychological well-being. Assessment of fulfillment of expectations is an important but infrequ...

Introduction The lateral transpsoas approach for lumbar interbody fusion (LLIF) is a minimally invasive surgical technique that is now frequently used to treat common spinal disorders. During LLIF, the course of the plexus within the surgical corridor places it at risk for iatrogenic intraoperative injury. Several previous studies have suggested that the risk of neurological injury during LLIF is higher at L4–L5. Current imaging techniques of assessing the proximity of neural tissue to the L4–L5 disc space have limited capabilities. Magnetic resonance neurography (MRN) is a noninvasive MR imaging tool developed for peripheral nerve imaging. A myriad of clinical applications exist including imaging assessment of lumbosacral plexopathies. In this study, we explored an additional clinical application for this technology as a preoperative planning tool for LLIF. Material and Methods Consecutive lumbar plexus MR neurograms ( n = 27 patients, 54 sides) were studied. All scans were performed on a Siemens 3 T Skyra MRI scanner. The imaging protocol included axial and coronal T1-weighted, axial and coronal T2-weighted spectral adiabatic inversion recovery (SPAIR; Siemens Healthcare), and coronal T2-weighted 3D inversion recovery (3D SPACE; Siemens Healthcare) sequences. Following acquisition, the images were postprocessed using TeraRecon Aquarius iNtuition v4.4 to generate T1- and T2- color-coded fusion maps. 3D models of the lumbosacral plexus with attention to the L4–L5 interspace were generated using the GE AW Suite v2 (General Electric). The L4–L5 intervertebral space was divided into six zones according to Moro method. Zones I to IV were distributed equidistantly between the anterior and posterior margins. The position of the plexus and the shape of the psoas muscle at the L4–L5 interspace was evaluated and recorded. Results Direct imaging of the lumbar plexus using MR neurography revealed variability in the position of the plexus relative to the L4–L5 interbody space. In this series of 27 patients, there was significant variability in the anatomic position of the lumbar plexus from patient-to-patient and right-to-left in individual patients. The left-side lumbar plexus was identified in zones III (55%) and zone IV (44%) ( p = 0.56). On the right side the plexus was most frequently identified in zones III (44%) or zone IV (44%) however was also identified in zone II (7.4%) or posterior (3.7%) ( p = 0.009). Right–left symmetry of the plexus relative to the disc space was found in 44% of the subjects. There was no correlation between the position of the plexus and the shape the overlying psoas muscle identified. Conclusion MRN is a noninvasive imaging technique for visualizing the lumbosacral plexus. The course of the lumbosacral plexus traversing the L4–5 disc space may be more variable than has been suggested by previous studies. MRN may provide a more reliable means of preoperatively identifying the plexus when compared with current methods. The ability to assess the location of the plexus may aid in preoperative planning and reduce neurological complications.

Background— Cell transplantation for myocardial repair is limited by early cell death. Gene therapy with human Bcl-2 (hBcl-2) has been shown to attenuate apoptosis in the experimental setting. Therefore, we studied the potential benefit of hBcl-2 transgene expression on the survival of cardiomyoblast grafts in ischemic rat hearts. Methods and Results— H9c2 rat cardiomyoblasts were genetically modified to express both firefly luciferase and green fluorescent protein (mH9c2). The cells were then transduced with adenovirus carrying hBcl-2 (AdCMVhBcl-2/mH9c2). Lewis rats underwent ligation of the left anterior descending artery (LAD) to induce a sizable left ventricular (LV) infarct. Hearts were explanted and the infarcted region was restored using collagen matrix (CM) seeded with 1×10 6 mH9c2 cells (n=9) or AdCMVhBcl-2/mH9c2 cells (n=9). Control animals received CM alone (n=6) or no infarct (n=6). Restored hearts were transplanted into the abdomen of syngeneic recipients in a “working heart” model. Cell survival was evaluated using optical bioluminescence imaging on days 1, 5, 8, 14, and 28 after surgery. The left heart function was assessed 4 weeks postoperatively using echocardiography and magnetic resonance imaging. During 4 weeks after surgery, the optical imaging signal for the AdCMVhBCL2/mH9c2 group was significantly ( P P =0.04) and ejection fraction (AdCMVhBcl-2/mH9c2: 47.0±6.2; mH9c2: 48.7±6.1; control: 34.3±6.0; P =0.02) compared with controls. Importantly, no malignant cells were found in postmortem histology. Conclusion— Transduction of mH9c2 cardiomyoblasts with AdCMVhBcl-2 increased graft survival in ischemic rat myocardium without causing malignancies. Both AdCMVhBcl-2/mH9c2 and mH9c2 grafts improved LV function.

Objective: A major limitation of stem cell transfer is early donor-cell death. Here, we seek to enhance myocardial repair following injury through transplantation of cardiomyocyte-enriched human embryonic stem cells (hESC) and recipient treatment with cytoprotective (allopurinol + uricase) and anti-inflammatory (ibuprofen) agents. Methods: We injected 106 (15% hESC-derived cardiomyocytes) green fluorescent protein (GFP+) hESC in the infarcted area following left anterior descending artery (LAD)-ligation in SCID-beige mice. In Group I, 1.6 mg allopurinol and 0.2 mg of uricase were injected i.p. for 3 days prior to cell transplantation. In Group II, 0.35 mg/ml of ibuprofen were added to the drinking water before and after cell implantation. In Group III, the LAD was ligated and allopurinol/uricase was administered without cell treatment. In Group IV, ibuprofen was added to the drinking water and the LAD was ligated without additional cell treatment. In Group V, only cells were transplanted. Group VI involved infarcted controls and Group VII involved sham-operated mice (all groups: n = 5). We evaluated heart function (ejection fraction (EF)) by MRI (4.7 T) 3 weeks later. The hearts were harvested for histology. Results: Differentiated hESC formed clusters and expressed α-sarcomeric actin and Connexin 43. Cell treatment improved heart function, which was best in the ibuprofen- and allopurinol-treated groups (+cell transfer), compared to the infarcted controls [EF: Group I: 76.6 ± 8.6%, Group II: 78.6 ± 7.3%, Group III: 58.1 ± 5.7%, Group IV: 53.9 ± 5.2%, Group V: 57.7 ± 7.5%, Group VI: 43.5 ± 4.3%, and Group VII: 66.3 ± 7.8%]. We did not observe tumors in any group. Conclusions: Allopurinol/uricase and ibuprofen enhance differentiated hESC-engraftment and myocardial restoration following transplantation into the injured heart. © 2005 Elsevier B.V. All rights reserved.

Background— Implantation of bioartificial patches distorts myocardial geometry, and functional improvement of the recipient heart is usually attributed to reactive angiogenesis around the graft. With the liquid bioartificial tissue compound used in this study, we achieved targeted large-scale support of the infarcted left ventricular wall and improvement of heart function. Methods and Results— A liquid compound consisting of growth factor-free Matrigel and 10 6 green fluorescent protein (GFP)-positive mouse (129sv) embryonic stem cells (ESCs) was generated and injected into the area of ischemia after ligation of the left anterior descending artery in BALB/c mice (group I). Left anterior descending artery-ligated mice (group II) and mice with Matrigel (group III) or ESC treatment alone (group IV) were used as the control groups (n=5 in all groups). The hearts were harvested for histology 2 weeks later after echocardiographic assessment with a 15-MHz probe. The liquid injectable tissue solidified at body temperature and retained the geometry of the infarcted lateral wall. Immunofluorescence stains revealed voluminous GFP grafts. The quality of restoration (graft/infarct area ratio) was 45.5±10.8% in group I and 29.1±6.7% in group IV ( P =0.034). ESCs expressed connexin 43 at intercellular contact sites. The mice treated with the compound had a superior heart function compared with the controls ( P Conclusions— Injectable bioartificial tissue restores the heart’s geometry and function in a targeted and nondistorting fashion. This new method paves the way for novel interventional approaches to myocardial repair, using both stem cells and matrices.

Background— We investigated whether differentiation of embryonic stem cells (ESCs) in ischemic myocardium enhances their immunogenicity, thereby increasing their chance for rejection. Methods and Results— In one series, 129/SvJ-derived mouse ESCs (ES-D3 line) were transplanted by direct myocardial injection (1×10 6 cells) into murine hearts of both allogeneic (BALB/c, n=20) and syngeneic (129/SvJ, n=12) recipients after left anterior artery ligation. Hearts were procured at 1, 2, 4, and 8 weeks after ESC transplantation and analyzed by immunohistochemistry to assess immune cell infiltration (CD3, CD4, CD8, B220, CD11c, Mac-1, and Gr-1) and ESC differentiation (hematoxylin and eosin). In a second series (allogeneic n=5, sham n=3), ESC transplantation was performed similarly; however after 2 weeks, left anterior descending artery-ligated and ESC-injected hearts were heterotopically transplanted into naive BALB/c recipients. After an additional 2 weeks, donor hearts were procured and analyzed by immunohistochemistry. In the first series, the size of all ESC grafts remained stable and there was no evidence of ESC differentiation 2 weeks after transplantation; however, after 4 weeks, both allogeneic and syngeneic ESC grafts showed the presence of teratoma. By 8 weeks, surviving ESCs could be detected in the syngeneic but not in the allogeneic group. Mild inflammatory cellular infiltrates were found in allogeneic recipients at 1 and 2 weeks after transplantation, progressing into vigorous infiltration at 4 and 8 weeks. The second series demonstrated similar vigorous infiltration of immune cells as early as 2 weeks after heterotopic transplantation. Conclusion— In vivo differentiated ESCs elicit an accelerated immune response as compared with undifferentiated ESCs. These data imply that clinical transplantation of allogeneic ESCs or ESC derivatives for treatment of cardiac failure might require immunosuppressive therapy.

The inaugural complex cervical spine symposium at the Hospital for Special Surgery brought together preeminent thought leaders and innovators in cervical spinal surgery in May of 2013 from around the USA, Europe, and Asia. Topics included advanced cervical spine operative techniques, cervical spine reconstruction, the operative treatment of pediatric cervical spine disorders, deformity, and tumor treatment at the occipitocervical junction. The Keynote Lecture was delivered by Kuniyoshi Abumi, MD, PhD, from Sapporo, Japan, on cervical spine osteotomies and the treatment and reduction of occiptiocervical deformities. Dr. Abumi served as the first president of the Cervical Spine Research Society’s Asia Pacific Division and is widely regarded for developing the technique of subaxial cervical spine pedicle screw instrumentation. Pediatric cervical spine lectures were given by John Dorman’s MD from the Children’s Hospital of Pennsylvania and Daniel Hedequist, MD, from Boston Children’s Hospital. Christoph Seipe, MD, PhD from the Schon Klinik in Munich, Germany, and Roger Hartl, MD, presented their experiences with advanced computer navigation techniques for complex degenerative cervical spine disorders and minimally invasive surgical techniques, respectively. Todd Albert, MD, who has since joined the HSS family as Surgeon-in-Chief, presented techniques for reconstruction of the post-surgical spine, and Edward D. Simmons, MD, presented the experience that he and his father accumulated over several decades with the cervical spine osteotomy that bears his family name, the “Simmon’s osteotomy.” Several controversial topics pertinent to modern cervical surgery were debated by leading experts in their respective fields, ranging from motion preservation surgery using disk replacement devices, the treatment of athletes with critical cervical spinal stenosis, and the optimal surgical approach for cervical spondylotic myelopathy using modern techniques. It was my great privilege both to serve as the director of the HSS Complex Cervical Spine Symposium and as guest editor of the HSS Journal’s cervical spine special issue. This focus issue of the symposium summarizes many of the cutting edge talks, debate sessions, and expert techniques given by surgeons at the symposium.

The lateral lumbar interbody fusion (LLIF) is a relatively new technique that allows the surgeon to access the intervertebral space from a direct lateral approach either anterior to or through the psoas muscle. This approach provides an alternative to anterior lumbar interbody fusion with instrumentation, posterior lumbar interbody fusion, and transforaminal lumbar interbody fusion for anterior column support. LLIF is minimally invasive, safe, better structural support from the apophyseal ring, potential for coronal plane deformity correction, and indirect decompression, which have has made this technique popular. LLIF is currently being utilized for a variety of pathologies including but not limited to adult de novo lumbar scoliosis, central and foraminal stenosis, spondylolisthesis, and adjacent segment degeneration. Although early clinical outcomes have been good, the potential for significant neurological and vascular vertebral endplate complications exists. Nevertheless, LLIF is a promising technique with the potential to more effectively treat complex adult de novo scoliosis and achieve predictable fusion while avoiding the complications of traditional anterior surgery and posterior interbody techniques.

Cardiothoracic Surgery/Falk Research Center, Stanford University Medical School, Stanford, CA, USA Department of Radiology, Stanford University Medical School, Stanford, CA, USA Geron Corporation, Menlo Park, CA, USA Division of Thoracic and Cardiovascular Surgery, Hannover Medical School, Carl Neuberg Street 1, 30625 Hannover, Germany www.elsevier.com/locate/ejcts European Journal of Cardio-thoracic Surgery 29 (2006) 1069

Traumatic thoracic aortic injury (TAI) is traditionally treated with immediate surgery. Previously published studies have established the safety and efficacy of treating TAI with endovascular stents. Our hypothesis was that stents are supplanting operative repair as the primary therapy for TAI.Retrospective cohort.University level I trauma center.Blunt trauma patients admitted to a level I trauma center diagnosed with TAI between September 1997 and November 2003 were identified from an institutional trauma registry (N = 25). Data were abstracted from medical records and analyzed. Three groups were defined: surgical repair (cardiopulmonary bypass or clamp and sew) (n = 10); medical management (n = 8); and endovascular stent (n = 7).Prior to 2002, 9 (75%) of 12 patients were treated by surgical repair, 2 (17%) by medical management, and 1 (8%) by endovascular stent. Since 2002, 1 patient (8%) was treated by surgical repair, 6 (46%) by medical management, and 6 (46%) by endovascular stent. Injury Severity Scores were comparable between the surgical cohort (mean +/- SEM score, 34.9 +/- 3.4), stent placement (35.1 +/- 3.7), and medical management (29.9 +/- 2.8) (P = .48). Overall survival was 80% with no differences in morbidity or mortality. The stented group had shorter hospital lengths of stay compared with surgical management (28 vs 46 days) (P.05). The 1 operative case since 2002 was a combined arch/innominate injury that anatomically precluded stent placement.Initial reports suggested thoracic aortic stents as an alternative for injured patients with prohibitive operative risks. Our data suggest stent placement is quickly evolving into the primary therapy for TAI across all Injury Severity Score profiles.

Objective The optimal surgical procedure for the neck in patients with squamous head and neck cancers is controversial. Selective neck dissections have replaced modified radical neck dissections as the procedure of choice for the clinically negative (N0) neck and are now being considered for patients with early-stage neck disease. We report the long-term local recurrence rates in 100 consecutive patients undergoing a radical or modified radical neck dissection for clinically positive (N+) and N0 neck disease and review comprehensively the literature reporting and comparing regional control rates for both neck dissection types. Patients The clinical records of 100 consecutive patients who underwent a comprehensive neck dissection (levels I-V) for squamous head and neck cancers with a minimum of a 2-year follow-up were retrospectively reviewed for primary site of disease, clinical and pathologic neck status, histopathologic grade, neck dissection type, and the site and time of recurrence. Results Complete data were available for 97 patients on whom 99 neck dissections were performed. Three patients died from unknown causes. Seventy-six patients with N+ disease underwent a therapeutic neck dissection, while 24 patients with clinically N0 disease underwent an elective dissection. The overall neck recurrence rate in patients with controlled primary disease was 7%. The neck or regional failure rate for patients completing the recommended adjuvant radiotherapy was 4%. Six (25%) of 24 patients with clinically N0 disease had occult metastases. The recurrence rate for this group was 4%. Conclusion Further study is needed to determine the optimal surgical management of the N0 and limited N+ neck.