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Dong-Hyuk Park, Prem Ramakrishnan, Tai-Hyoung Cho, Eric Lorenz, Jason C. Eck, S. Craig Humphreys and Tae-Hong Lim


Symptomatic multisegment disease is most common at the C5–6 and C6–7 levels, and two-level anterior cervical discectomy and fusion (ACDF) is performed most often at these levels. Therefore, it may be clinically important to know whether a C5–7 fusion affects the superior C4–5 segment. A biomechanical study was carried out using cadaveric cervical spine specimens to determine the effect of lower two-level anterior cervical fusion on intradiscal pressure and segmental motion at the superior adjacent vertebral level.


Five cadaveric cervical spine specimens were used in this study. The specimens were stabilized at T-1 and loaded at C-3 to 15° flexion, 10° extension, and 10° lateral bending before and after simulated two-level ACDF with plate placement at C5–7. Intradiscal pressure was recorded at the C4–5 level, and segmental motion was recorded from C-4 through C-7. Differences in mean intradiscal pressures were calculated and analyzed using a paired Student t-test. When the maximum calibrated intradiscal pressures were exceeded (“overshot”) during measurements, data from the specimens involved were analyzed using the motion data with a Student t-test. Values for pressure and motion obtained before and after simulated ACDF were compared.


During flexion, the mean intradiscal pressure changes (± standard deviations) in the pre- and post-ACDF measurements were 1275 (± 225) mm Hg and 2475 (± 75) mm Hg, respectively (p < 0.05). When the results of pre-ACDF testing were compared with post-ACDF results, no significant difference was found in the mean changes in the intradiscal pressure during extension and lateral bending. The maximum calibrated intradiscal pressures were exceeded during the post-ACDF testing in four specimens in extension, three in flexion, and two in lateral bending. Comparison of pre- and post-ACDF data for all five specimens revealed significant differences in motion and intradiscal pressure (p < 0.05) during flexion, significant differences in motion (p < 0.05) but not in intradiscal pressure during extension, and significant differences in intradiscal pressure changes (p < 0.05) but not in motion during lateral bending.


Simulated C5–7 ACDF caused a significant increase in intradiscal pressure and segmental motion in the superior adjacent C4–5 level during physiological motion. The increased pressure and hypermobility might accelerate normal degenerative changes in the vertebral levels adjacent to the anterior cervical fusion.

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Zoher Ghogawala, Robert G. Whitmore, William C. Watters III, Alok Sharan, Praveen V. Mummaneni, Andrew T. Dailey, Tanvir F. Choudhri, Jason C. Eck, Michael W. Groff, Jeffrey C. Wang, Daniel K. Resnick, Sanjay S. Dhall and Michael G. Kaiser

A comprehensive economic analysis generally involves the calculation of indirect and direct health costs from a societal perspective as opposed to simply reporting costs from a hospital or payer perspective. Hospital charges for a surgical procedure must be converted to cost data when performing a cost-effectiveness analysis. Once cost data has been calculated, quality-adjusted life year data from a surgical treatment are calculated by using a preference-based health-related quality-of-life instrument such as the EQ-5D. A recent cost-utility analysis from a single study has demonstrated the long-term (over an 8-year time period) benefits of circumferential fusions over stand-alone posterolateral fusions. In addition, economic analysis from a single study has found that lumbar fusion for selected patients with low-back pain can be recommended from an economic perspective. Recent economic analysis, from a single study, finds that femoral ring allograft might be more cost-effective compared with a specific titanium cage when performing an anterior lumbar interbody fusion plus posterolateral fusion.

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Andrew T. Dailey, Zoher Ghogawala, Tanvir F. Choudhri, William C. Watters III, Daniel K. Resnick, Alok Sharan, Jason C. Eck, Praveen V. Mummaneni, Jeffrey C. Wang, Michael W. Groff, Sanjay S. Dhall and Michael G. Kaiser

The utilization of orthotic devices for lumbar degenerative disease has been justified from both a prognostic and therapeutic perspective. As a prognostic tool, bracing is applied prior to surgery to determine if immobilization of the spine leads to symptomatic relief and thus justify the performance of a fusion. Since bracing does not eliminate motion, the validity of this assumption is questionable. Only one low-level study has investigated the predictive value of bracing prior to surgery. No correlation between response to bracing and fusion outcome was observed; therefore a trial of preoperative bracing is not recommended. Based on low-level evidence, the use of bracing is not recommended for the prevention of low-back pain in a general working population, since the incidence of low-back pain and impact on productivity were not reduced. However, in laborers with a history of back pain, a positive impact on lost workdays was observed when bracing was applied. Bracing is recommended as an option for treatment of subacute low-back pain, as several higher-level studies have demonstrated an improvement in pain scores and function. The use of bracing following instrumented posterolateral fusion, however, is not recommended, since equivalent outcomes have been demonstrated with or without the application of a brace.

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Michael G. Kaiser, Jason C. Eck, Michael W. Groff, William C. Watters III, Andrew T. Dailey, Daniel K. Resnick, Tanvir F. Choudhri, Alok Sharan, Jeffrey C. Wang, Praveen V. Mummaneni, Sanjay S. Dhall and Zoher Ghogawala

Fusion procedures are an accepted and successful management strategy to alleviate pain and/or neurological symptoms associated with degenerative disease of the lumbar spine. In 2005, the first version of the “Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine” was published in the Journal of Neurosurgery: Spine. In an effort to incorporate evidence obtained since the original publication of these guidelines, an expert panel of neurosurgical and orthopedic spine specialists was convened in 2009. Topics reviewed were essentially identical to the original publication. Selected manuscripts from the first iteration of these guidelines as well as relevant publications between 2005 through 2011 were reviewed. Several modifications to the methodology of guideline development were adopted for the current update. In contrast to the 2005 guidelines, a 5-tiered level of evidence strategy was employed, primarily allowing a distinction between lower levels of evidence. The qualitative descriptors (standards/guidelines/options) used in the 2005 recommendations were abandoned and replaced with grades to reflect the strength of medical evidence supporting the recommendation. Recommendations that conflicted with the original publication, if present, were highlighted at the beginning of each chapter. As with the original guideline publication, the intent of this update is to provide a foundation from which an appropriate treatment strategy can be formulated.

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Tanvir F. Choudhri, Praveen V. Mummaneni, Sanjay S. Dhall, Jason C. Eck, Michael W. Groff, Zoher Ghogawala, William C. Watters III, Andrew T. Dailey, Daniel K. Resnick, Alok Sharan, Jeffrey C. Wang and Michael G. Kaiser

The ability to identify a successful arthrodesis is an essential element in the management of patients undergoing lumbar fusion procedures. The hypothetical gold standard of intraoperative exploration to identify, under direct observation, a solid arthrodesis is an impractical alternative. Therefore, radiographic assessment remains the most viable instrument to evaluate for a successful arthrodesis. Static radiographs, particularly in the presence of instrumentation, are not recommended. In the absence of spinal instrumentation, lack of motion on flexion-extension radiographs is highly suggestive of a successful fusion; however, motion observed at the treated levels does not necessarily predict pseudarthrosis. The degree of motion on dynamic views that would distinguish between a successful arthrodesis and pseudarthrosis has not been clearly defined. Computed tomography with fine-cut axial images and multiplanar views is recommended and appears to be the most sensitive for assessing fusion following instrumented posterolateral and anterior lumbar interbody fusions. For suspected symptomatic pseudarthrosis, a combination of techniques including static and dynamic radiographs as well as CT images is recommended as an option. Lack of facet fusion is considered to be more suggestive of a pseudarthrosis compared with absence of bridging posterolateral bone. Studies exploring additional noninvasive modalities of fusion assessment have demonstrated either poor potential, such as with 99mTc bone scans, or provide insufficient information to formulate a definitive recommendation.

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Sanjay S. Dhall, Tanvir F. Choudhri, Jason C. Eck, Michael W. Groff, Zoher Ghogawala, William C. Watters III, Andrew T. Dailey, Daniel K. Resnick, Alok Sharan, Praveen V. Mummaneni, Jeffrey C. Wang and Michael G. Kaiser

In an effort to diminish pain or progressive instability, due to either the pathological process or as a result of surgical decompression, one of the primary goals of a fusion procedure is to achieve a solid arthrodesis. Assuming that pain and disability result from lost mechanical integrity of the spine, the objective of a fusion across an unstable segment is to eliminate pathological motion and improve clinical outcome. However, conclusive evidence of this correlation, between successful fusion and clinical outcome, remains elusive, and thus the necessity of documenting successful arthrodesis through radiographic analysis remains debatable. Although a definitive cause and effect relationship has not been demonstrated, there is moderate evidence that demonstrates a positive association between radiographic presence of fusion and improved clinical outcome. Due to this growing body of literature, it is recommended that strategies intended to enhance the potential for radiographic fusion are considered when performing a lumbar arthrodesis for degenerative spine disease.

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Jason C. Eck, Alok Sharan, Daniel K. Resnick, William C. Watters III, Zoher Ghogawala, Andrew T. Dailey, Praveen V. Mummaneni, Michael W. Groff, Jeffrey C. Wang, Tanvir F. Choudhri, Sanjay S. Dhall and Michael G. Kaiser

Identifying the etiology of pain for patients suffering from chronic low-back pain remains problematic. Noninvasive imaging modalities, used in isolation, have not consistently provided sufficient evidence to support performance of a lumbar fusion. Provocative testing has been used as an adjunct in this assessment, either alone or in combination with other modalities, to enhance the diagnostic capabilities when evaluating patients with low-back pain. There have been a limited number of studies investigating this topic since the publication of the original guidelines. Based primarily on retrospective studies, discography, as a stand-alone test, is not recommended to formulate treatment strategies for patients with low-back pain. A single randomized cohort study demonstrated an improved potential of discoblock over discography as a predictor of success following lumbar fusion. It is therefore recommended that discoblock be considered as a diagnostic option. There is a possibility, based on a matched cohort study, that an association exists between progression of degenerative disc disease and the performance of a provocative discogram. It is therefore recommended that patients be counseled regarding this potential development prior to undergoing discography.

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Jason C. Eck, Alok Sharan, Zoher Ghogawala, Daniel K. Resnick, William C. Watters III, Praveen V. Mummaneni, Andrew T. Dailey, Tanvir F. Choudhri, Michael W. Groff, Jeffrey C. Wang, Sanjay S. Dhall and Michael G. Kaiser

Establishing an appropriate treatment strategy for patients presenting with low-back pain, in the absence of stenosis or spondylolisthesis, remains a controversial subject. Inherent to this situation is often an inability to adequately identify the source of low-back pain to justify various treatment recommendations, such as lumbar fusion. The current evidence does not identify a single best treatment alternative for these patients. Based on a number of prospective, randomized trials, comparable outcomes, for patients presenting with 1- or 2-level degenerative disc disease, have been demonstrated following either lumbar fusion or a comprehensive rehabilitation program with a cognitive element. Limited access to such comprehensive rehabilitative programs may prove problematic when pursuing this alternative. For patients whose pain is refractory to conservative care, lumbar fusion is recommended. Limitations of these studies preclude the ability to present the most robust recommendation in support of lumbar fusion. A number of lesser-quality studies, primarily case series, also support the use of lumbar fusion in this patient population.

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Jeffrey C. Wang, Andrew T. Dailey, Praveen V. Mummaneni, Zoher Ghogawala, Daniel K. Resnick, William C. Watters III, Michael W. Groff, Tanvir F. Choudhri, Jason C. Eck, Alok Sharan, Sanjay S. Dhall and Michael G. Kaiser

Patients suffering from a lumbar herniated disc will typically present with signs and symptoms consistent with radiculopathy. They may also have low-back pain, however, and the source of this pain is less certain, as it may be from the degenerative process that led to the herniation. The surgical alternative of choice remains a lumbar discectomy, but fusions have been performed for both primary and recurrent disc herniations. In the original guidelines, the inclusion of a fusion for routine discectomies was not recommended. This recommendation continues to be supported by more recent evidence. Based on low-level evidence, the incorporation of a lumbar fusion may be considered an option when a herniation is associated with evidence of spinal instability, chronic low-back pain, and/or severe degenerative changes, or if the patient participates in heavy manual labor. For recurrent disc herniations, there is low-level evidence to support the inclusion of lumbar fusion for patients with evidence of instability or chronic low-back pain.

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Daniel K. Resnick, William C. Watters III, Praveen V. Mummaneni, Andrew T. Dailey, Tanvir F. Choudhri, Jason C. Eck, Alok Sharan, Michael W. Groff, Jeffrey C. Wang, Zoher Ghogawala, Sanjay S. Dhall and Michael G. Kaiser

Lumbar stenosis is one of the more common radiographic manifestations of the aging process, leading to narrowing of the spinal canal and foramen. When stenosis is clinically relevant, patients often describe activity-related low-back or lower-extremity pain, known as neurogenic claudication. For those patients who do not improve with conservative care, surgery is considered an appropriate treatment alternative. The primary objective of surgery is to reconstitute the spinal canal. The role of fusion, in the absence of a degenerative deformity, is uncertain. The previous guideline recommended against the inclusion of lumbar fusion in the absence of spinal instability or a likelihood of iatrogenic instability. Since the publication of the original guidelines, numerous studies have demonstrated the role of surgical decompression in this patient population; however, few have investigated the utility of fusion in patients without underlying instability. The majority of studies contain a heterogeneous cohort of subjects, often combining patients with and without spondylolisthesis who received various surgical interventions, limiting fusions to those patients with instability. It is difficult if not impossible, therefore, to formulate valid conclusions regarding the utility of fusion for patients with uncomplicated stenosis. Lower-level evidence exists, however, that does not demonstrate an added benefit of fusion for these patients; therefore, in the absence of deformity or instability, the inclusion of a fusion is not recommended.