Surgical intervention is indicated for pyogenic vertebral discitis and osteomyelitis in patients in whom medical therapy has failed, and in those with neurological compromise, mechanical instability, epidural abscess, or intractable pain. Surgical management has evolved to include single-stage operations for debridement and stabilization as well as more aggressive reconstruction strategies with respect to instrumentation. A review of the literature demonstrates excellent outcomes with single-stage operations and placement of hardware wherever it is required. Using this method, the authors have treated 16 patients without a single incidence of recurrent infection or hardware failure after almost 2 years of follow up.
Alfred T. Ogden and Michael G. Kaiser
State of the union: a review of lumbar fusion indications and techniques for degenerative spine disease
JNSPG 75th Anniversary Invited Review Article
Patrick C. Reid, Simon Morr and Michael G. Kaiser
Lumbar fusion is an accepted and effective technique for the treatment of lumbar degenerative disease. The practice has evolved continually since Albee and Hibbs independently reported the first cases in 1913, and advancements in both technique and patient selection continue through the present day. Clinical and radiological indications for surgery have been tested in trials, and other diagnostic modalities have developed and been studied. Fusion practices have also advanced; instrumentation, surgical approaches, biologics, and more recently, operative planning, have undergone stark changes at a seemingly increasing pace over the last decade. As the general population ages, treatment of degenerative lumbar disease will become a more prevalent—and costlier—issue for surgeons as well as the healthcare system overall. This review will cover the evolution of indications and techniques for fusion in degenerative lumbar disease, with emphasis on the evidence for current practices.
Brian R. Subach, Regis W. Haid, Gerald E. Rodts and Michael G. Kaiser
The widespread use of fusion procedures in the management of spinal disorders has led investigators to explore the use of growth and differentiation factors in such procedures. As an adjuvant to allograft bone or as a replacement for harvested autograft, bone morphogenetic proteins (BMPs) appear to improve fusion rates after spinal arthrodesis in both animal models and humans, while reducing the donor-site morbidity previously associated with such procedures. The use of recombinant genetic technology in the production of BMP has improved the efficiency, cost effectiveness, and safety of producing and using such materials. Recombinant human BMP-2 (rhBMP-2), as one of the first factors identified in the process of endochondral bone formation, has been extensively researched over the past decade. The efficacy and dose profile of this differentiation factor in the context of various carrier substrates has been investigated. Based on the encouraging results of preliminary studies, the future role of rhBMP-2 may lie in its replacement of autologous bone grafting and, consequently, the reduced need for instrumented fixation, while concurrently improving overall fusion rates. The authors provide an overview of BMP and review its use in clinical and laboratory settings.
Christopher E. Mandigo, Prakash Sampath and Michael G. Kaiser
✓Posterior dynamic stabilization in the lumbar spine is performed in an attempt to reduce loading across the intervertebral disc for the purpose of relieving pain and limiting degeneration while preserving motion. The AccuFlex rod system (Globus Medical, Inc.), a first-generation device, achieves this by changing the properties of the rod within the Protex pedicle screw–based rigid rod system. Helical cuts that have been created in the standard 6.5-mm rod allow for a limited range of motion while providing a posterior tension band that relieves a significant amount of disc loading. The AccuFlex rod system has been approved by the Food and Drug Administration for single-level fusion when used in conjunction with an interbody graft. In a study involving 170 patients who underwent fusion surgery for back pain, the 54 who received the AccuFlex construct had statistically similar fusion rates and outcomes (as assessed by visual analog scale and Short Form-16 scores) when compared with 116 patients treated with rigid rod fixation after 1 year of follow up. Future clinical studies will examine and provide information regarding the impact of AccuFlex on the incidence of adjacent-level disease. Information gained through the clinical experience with AccuFlex will serve as a foundation for the development of a stand-alone dynamic construct.
Ismail H. Tekkök
Report of two cases in adults and review of the literature
Alfred T. Ogden, Alexander G. Khandji, Paul C. McCormick and Michael G. Kaiser
✓Intramedullary inclusion cysts are extremely rare within the rostral spinal cord. In this case report the authors outline the clinical features and surgical treatment of one dermoid cyst and one epidermoid cyst of the cervicothoracic junction. The authors also include a relevant literature discussion regarding the treatment and the embryological origin of these lesions.
Case report and review of the literature
Allen Waziri, Jean-Paul Vonsattel, Michael G. Kaiser and Richard C. E. Anderson
✓The authors describe the case of a patient with an enhancing, intramedullary cervical spinal cord lesion and associated syrinx. Biopsy sampling of the cervical lesion was performed, and the histological findings were consistent with a demyelinating process supporting the diagnosis of multiple sclerosis (MS). Syrinx formation associated with demyelinating disease has only been described in isolated cases, almost exclusively in Japanese patients with MS.
A 22-year-old woman of Caribbean descent presented with a subacute, progressive myelopathy including symptoms of pain and weakness in all extremities, bladder incontinence, and the inability to ambulate. Magnetic resonance imaging of the brain and spinal cord demonstrated an enlarged cervical cord with enhancement and central cavitation consistent with a syrinx.
The patient underwent a C3–7 laminoplasty and placement of a dural graft for cord decompression as well as fenestration of the central syrinx. Biopsy sampling of the lesion was performed, and the histopathological analysis, in conjunction with subsequent laboratory and diagnostic testing, supported the diagnosis of demyelinating disease. After treatment with a course of high-dose dexamethasone and inpatient rehabilitation therapy, the patient demonstrated significant clinical improvement.
Spinal cord involvement is not uncommon in patients with demyelinating disease; however, enhancing lesions associated with extensive tissue loss and syrinx formation have rarely been reported. For the consulting neurological surgeon, demyelinating disease should be included in the differential diagnosis of such lesions given the level of complexity and risk to the patient associated with open biopsy of the spinal cord.
Praveen V. Mummaneni, Michael G. Kaiser, Paul G. Matz, Paul A. Anderson, Michael Groff, Robert Heary, Langston Holly, Timothy Ryken, Tanvir Choudhri, Edward Vresilovic and Daniel Resnick
The objective of this systematic review was to use evidence-based medicine to assess whether preoperative imaging or electromyography (EMG) predicts surgical outcomes in patients undergoing cervical surgery.
The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to the preoperative imaging and EMG. Abstracts were reviewed after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.
Preoperative MR imaging and CT myelography are successful in confirming clinical radiculopathy (Class II). Multilevel T2 hyperintensity, T1 focal hypointensity combined with T2 focal hyperintensity, and spinal cord atrophy each convey a poor prognosis (Class III). There is conflicting data concerning whether focal T2 hyperintensity or cervical stenosis are associated with a worse outcome. Electromyography has mixed utility in predicting outcome (Class III).
Magnetic resonance imaging or CT myelography are important for preoperative assessment. Magnetic resonance imaging may be helpful in assessing prognosis, whereas EMG has mixed utility in assessing outcome.