Robert E. Isaacs

A Prospective, Nonrandomized, Multicenter Evaluation of Extreme Lateral Interbody Fusion for the Treatment of Adult Degenerative Scoliosis: Perioperative Outcomes and Complications

Study Design. Prospective multicenter nonrandomized institutional review board-approved observational study of clinical and radiographic outcomes of the extreme lateral interbody fusion (XLIF) procedure in adult scoliosis. Objective. Perioperative measures from this longitudinal study were compiled to identify the short-term results and complications of the procedure. Summary of Background Data. The surgical treatment of adult scoliosis presents a treatment challenge. Neural decompression with combined anterior/posterior instrumented fusion is often performed. These procedures have been reported to carry a high risk of complication, particularly in the elderly patient population. Over the past decade, less invasive surgical approaches to neural decompression and fusion have been popularized and have recently been applied in the treatment of degenerative scoliosis. To date, there has been little published data evaluating these treatment approaches. Methods. A total of 107 patients who underwent the XLIF procedure with or without supplemental posterior fusion for the treatment of degenerative scoliosis were prospectively studied. Intraoperative data collection included surgical procedural details, operative time, estimated blood loss, and surgical complications. Postoperative complications, length of hospital stay, and neurologic status were recorded. For this report, perioperative data (inclusive of outcomes through the 6-week postoperative clinic visit) were evaluated. Results. In all, 107 patients (mean age, 68 years; range, 45–87) were treated with XLIF; 28% had at least 1 comorbidity. A mean of 4.4 levels (range, 1–9) were treated per patient. Supplemental pedicle screw fixation was used in 75.7% of patients, 5.6% had lateral fixation, and 18.7% had stand-alone XLIF. Mean operative time and blood loss were 178 minutes (58 minutes/level) and 50 to 100 mL. Mean hospital stay was 2.9 days (unstaged), 8.1 day (staged, 16.5%), 3.8 days overall. Five patients (4.7%) received a transfusion, 3 (2.8%) required intensive care unit admission, and 1 (0.9%) required rehabilitation services. Major complications occurred in 13 patients (12.1%): 2 (1.9%) medical, 12 (11.2%) surgical. Of procedures that involved only less invasive techniques (XLIF stand-alone or with percutaneous instrumentation), 9.0% had one or more major complications. In those with supplemental open posterior instrumentation, 20.7% had one or more major complication. Early reoperations (3) (all for deep wound infections) were associated with open posterior instrumentation procedures. Conclusion. The morbidity in adult scoliosis surgery is minimized with less invasive techniques. The rate of major complications in this study (12.1%) compares favorably to that reported from other studies of surgery for degenerative deformity.

Proinflammatory cytokine expression profile in degenerated and herniated human intervertebral disc tissues

OBJECTIVE Prior reports document macrophage and lymphocyte infiltration with proinflammatory cytokine expression in pathologic intervertebral disc (IVD) tissues. Nevertheless, the role of the Th17 lymphocyte lineage in mediating disc disease remains uninvestigated. We undertook this study to evaluate the immunophenotype of pathologic IVD specimens, including interleukin-17 (IL-17) expression, from surgically obtained IVD tissue and from nondegenerated autopsy control tissue. METHODS Surgical IVD tissues were procured from patients with degenerative disc disease (n = 25) or herniated IVDs (n = 12); nondegenerated autopsy control tissue was also obtained (n = 8) from the anulus fibrosus and nucleus pulposus regions. Immunohistochemistry was performed for cell surface antigens (CD68 for macrophages, CD4 for lymphocytes) and various cytokines, with differences in cellularity and target immunoreactivity scores analyzed between surgical tissue groups and between autopsy control tissue regions. RESULTS Immunoreactivity for IL-4, IL-6, IL-12, and interferon-gamma (IFNgamma) was modest in surgical IVD tissue, although expression was higher in herniated IVD samples and virtually nonexistent in control samples. The Th17 lymphocyte product IL-17 was present in >70% of surgical tissue fields, and among control samples was detected rarely in anulus fibrosus regions and modestly in nucleus pulposus regions. Macrophages were prevalent in surgical tissues, particularly herniated IVD samples, and lymphocytes were expectedly scarce. Control tissue revealed lesser infiltration by macrophages and a near absence of lymphocytes. CONCLUSION Greater IFNgamma positivity, macrophage presence, and cellularity in herniated IVDs suggests a pattern of Th1 lymphocyte activation in this pathology. Remarkable pathologic IVD tissue expression of IL-17 is a novel finding that contrasts markedly with low levels of IL-17 in autopsy control tissue. These findings suggest involvement of Th17 lymphocytes in the pathomechanism of disc degeneration.

Microendoscopic lumbar discectomy: technical note.

OBJECTIVE The microendoscopic discectomy (MED) technique was initially developed in 1997 to treat herniated lumbar disc disease. Since then, thousands of cases have been successfully performed at more than 500 institutions. This article discusses the technical aspects of this procedure and presents a consecutive case series. METHODS A total of 150 consecutive patients underwent MED. MED is performed by a muscle-splitting approach using a series of tubular dilators with consecutively increasing diameters. A tubular retractor is then inserted over the final dilator, and a specially designed endoscope is placed inside the tubular retractor. The microdiscectomy is performed endoscopically while the surgeon views the procedure on a video monitor. RESULTS Clinical outcomes were determined using a modified MacNab criteria, which revealed that 77% of patients had excellent, 17% had good, 3% had fair, and 3% had poor outcomes. The average hospital stay was 7.7 hours. The average return to work period was 17 days. Complications primarily included dural tears, which occurred in 8 patients (5%) and were seen early on in the patient series. Complication rates diminished as the surgeon’s experience with this technique increased. CONCLUSION MED for lumbar herniated disc disease can be performed safely and effectively, resulting in a shortened hospital stay and faster return to work; however, there is a learning curve to this procedure.

Minimally Invasive Spine Surgery

Paul C. McAfee, MD, MBA, Frank M. Phillips, MD, Gunnar Andersson, MD, PhD, Asokumar Buvenenadran, MD, Choll W. Kim, MD, Carl Lauryssen, MD, Robert E. Isaacs, MD, Jim A. Youssef, MD, Darrel S. Brodke, MD, Andrew Cappuccino, MD, Behrooz A. Akbarnia, MD, Gregory M. Mundis, MD, William D. Smith, MD, Juan S. Uribe, MD, Steve Garfin, MD, R. Todd Allen, MD, William Blake Rodgers, MD, Luiz Pimenta, MD, PhD, and William Taylor, MD

Work toward real-time control of a cortical neural prothesis

Implantable devices that interact directly with the human nervous system have been gaining acceptance in the field of medicine since the 1960s. More recently, as is noted by the FDA approval of a deep brain stimulator for movement disorders, interest has shifted toward direct communication with the central nervous system (CNS). Deep brain stimulation (DBS) can have a remarkable effect on the lives of those with certain types of disabilities such as Parkinsons disease, Essential Tremor, and dystonia. To correct for many of the motor impairments not treatable by DBS (e.g. quadriplegia), it would be desirable to extract from the CNS a control signal for movement. A direct interface with motor cortical neurons could provide an optimal signal for restoring movement. In order to accomplish this, a real-time conversion of simultaneously recorded neural activity to an online command for movement is required. A system has been established to isolate the cellular activity of a group of motor neurons and interpret their movement-related information with a minimal delay. The real-time interpretation of cortical activity on a millisecond time scale provides an integral first step in the development of a direct brain-computer interface (BCI).

Minimally invasive transforaminal lumbar interbody fusion: a review of techniques and outcomes.

Study Design. Review of published literature. Objective. To review the available medical literature reporting results after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) and evaluate functional and radiographic outcomes with those following open TLIF and open posterior lumbar interbody fusion (PLIF) procedures. Summary of Background Data. Minimally invasive spine techniques aim to reduce approach-related surgical morbidity without compromising operative and clinical outcomes. MIS TLIF is increasingly being used for the management of various lumbar degenerative diseases. Despite the limited number of well-designed clinical studies, the available published data suggest potential advantages over its open posterior-approach lumbar interbody fusion counterparts. Such benefits include less intraoperative blood loss, less need for blood transfusions, shorter hospital course, and less postoperative pain. Methods. Literature examining posterior-approach interbody fusion techniques (PLIF, TLIF, and MIS TLIF) was collected using the National Center for Biotechnology Information database and PubMed/MEDLINE, and summarized for discussion. Results. Literature reports of MIS TLIF generally show comparable or improved clinical outcomes when compared with those following open posterior interbody fusion techniques. Additionally, significantly less blood loss, hospital stay, and complications were generally reported, despite slightly longer duration of surgery, especially during early cases in a surgeons experience. Conclusion. More studies designed to provide class I or II data will be needed in the future to further solidify the favorable results observed so far with the MIS TLIF procedure.

STEREOTACTIC BODY RADIOTHERAPY FOR LESIONS OF THE SPINE AND PARASPINAL REGIONS

PURPOSE To describe our experience and clinical strategy for stereotactic body radiotherapy (SBRT) of spinal lesions. METHODS AND MATERIALS Thirty-two patients with 33 spinal lesions underwent computed tomography-based simulation while free breathing. Gross/clinical target volumes included involved portions of the vertebral body and paravertebral/epidural tumor. Planning target volume (PTV) expansion was 6 mm axially and 3 mm radially; the cord was excluded from the PTV. Biologic equivalent dose was calculated using the linear quadratic model with alpha/beta = 3 Gy. Treatment was linear accelerator based with on-board imaging; dose was adjusted to maintain cord dose within tolerance. Survival, local control, pain, and neurologic status were monitored. RESULTS Twenty-one patients are alive at 1 year (median survival, 14 months). Median follow-up is 6 months for all patients (7 months for survivors). Mean previous radiotherapy dose to 22 patients was 35 Gy, and median interval was 17 months. Renal (31%), breast, and lung (19% each) were the most common histologic sites. Three SBRT fractions (range, one to four fractions) of 7 Gy (range, 5-16 Gy) were delivered. Median cord and target biologic equivalent doses were 70 Gy(3) and 34.3 Gy(10), respectively. Thirteen patients reported complete and 17 patients reported partial pain relief at 1 month. There were four failures (mean, 5.8 months) with magnetic resonance imaging evidence of in-field progression. No dosimetric parameters predictive of failure were identified. No treatment-related toxicity was seen. CONCLUSIONS Spinal SBRT is effective in the palliative/re-treatment setting. Volume expansion must ensure optimal PTV coverage while avoiding spinal cord toxicity. The long-term safety of spinal SBRT and the applicability of the linear-quadratic model in this setting remain to be determined, particularly the time-adjusted impact of prior radiotherapy.

Impact of surgical approach on complications and resource utilization of cervical spine fusion: a nationwide perspective to the surgical treatment of diffuse cervical spondylosis

BACKGROUND CONTEXT Cervical spine fusion is performed for various indications in patient populations ranging from young and healthy to aged and frail. The choice of surgical approach is affected not only by disease pathoanatomy, but also by age, medical comorbidities, and the number of involved levels. Anterior fusion is more common for single-level pathology in relatively young, healthy patients; and posterior fusion is typically performed on older, more comorbid patients with multilevel disease. Consequently, retrospective comparisons of surgical approaches for cervical fusion will be impacted by this bias, and the optimal management of multilevel cervical spine pathology remains ambiguous with surgeon preference and experience playing a significant role in choice of procedures. PURPOSE To define the complications and resource utilization related to multilevel cervical spine fusion surgery, and to evaluate the impact of surgical approach on these outcomes. STUDY DESIGN/SETTING A retrospective nationwide database study of inpatient perioperative complications. PATIENT SAMPLE All patients undergoing multilevel (four to eight levels) cervical spine fusion for degenerative disease between 2003 and 2005 at institutions represented in the Nationwide Inpatient Sample database. OUTCOME MEASURES Measures of patient periprocedural mortality, selected specific morbidities, and resource utilization were evaluated. Resource utilization included length of hospitalization, inflation-adjusted cost, and likelihood of nonroutine discharge to assisted living. METHODS Data for 8,548 patients who underwent cervical fusion of four to eight levels were collected from the Nationwide Inpatient Sample database (2003-2005), and subjects were grouped by surgical approach (anterior vs. posterior). Descriptive statistics compared baseline characteristics, and bivariate analysis and logistic regression modeling evaluated the effect of surgical approach on mortality, selected postoperative complications, length of stay, hospitalization cost, and discharge disposition. All tests were performed at the 0.05 level of significance. RESULTS This observational study indicates that a posterior approach to multilevel cervical fusion is associated with more respiratory complications, postoperative infections, symptomatic hematomas, and transfusions when compared with an anterior approach. Resource utilization was nearly double for those undergoing a posterior approach, including hospital length of stay, inflation-adjusted cost, and likelihood of discharge to an assisted-living facility. Not surprisingly, this study confirms that patients fused posteriorly had a lower incidence of symptomatic postoperative dysphagia. CONCLUSIONS This nationwide study defines the incidence of mortality and the frequency of inpatient complications encountered during multilevel cervical fusion. The results suggest that immediate morbidity from anterior approaches is less than those undergoing posterior fusion. Prospective analysis is required to evaluate if these findings remain significant in a randomized study population. Further, these results represent only perioperative complications. However, based on the data presented herein, when confronted with the patient requiring a four-level cervical fusion, the anterior approach may offer a less risky and less costly option.

Complications associated with minimally invasive decompression for lumbar spinal stenosis.

Objective Surgical strategies for the decompression of lumbar spinal stenosis have evolved to include minimally invasive techniques providing for adequate and safe decompression while reducing perioperative morbidity. Retrospective case series analysis of 220 consecutive patients with lumbar spinal stenosis who underwent microscopic or microendoscopic minimally invasive decompression was performed. The objective was to evaluate the risks associated with performing a minimally invasive decompression for spinal stenosis in a large group of patients. Methods Two hundred twenty patients with symptomatic neurogenic claudication from lumbar spinal stenosis failing nonoperative treatment received a minimally invasive decompression surgery. Intraoperative data, postoperative data through hospital discharge, and clinical follow-up were analyzed. Results The average age was 74.2 years (range 49–98 years). There were 379 spinal levels decompressed in 220 patients. Sixty-nine patients (31.4%) had a grade 1 degenerative spondylolisthesis. One hundred sixty-eight patients (76%) received spinal anesthesia, and 52 received general anesthesia. Eighty-seven patients (40%) had a preoperative American Society of Anesthesiologists score of 3 or 4. Average operative blood loss was 92 mL. There were 17 intraoperative durotomies (4.5% rate). The average length of stay before discharge was 1.2 days. Ten patients went to inpatient rehabilitation at discharge. One hundred ninety-four patients (88.2%) were discharged within 24 hours. There were five readmissions within the first month after discharge, four of those for medical complications. There were 24 minor complications and 14 major complications. Forty-two patients (19%) took no oral or parenteral narcotic pain medications in the postanesthesia to discharge period. Conclusion Minimally invasive decompression strategies for spinal stenosis seem consistently to result in short hospital lengths of stay, minimal requirements for narcotic pain medications, and a low rate of readmission and complications.

Extreme lateral interbody fusion approach for isolated thoracic and thoracolumbar spine diseases: initial clinical experience and early outcomes.

Study Design Retrospective review of prospective collected data on 22 patients. Objective To describe our initial clinical experience and outcomes with the extreme lateral interbody fusion (XLIF) approach for spinal diseases requiring access to the thoracic cavity. Summary of Background Data Minimally invasive anterior approaches to the thoracic spine have traditionally consisted of thoracoscopic and mini-open thoracotomy techniques. We present our initial experience with employing the XLIF technique to treat thoracic spine diseases. Methods Clinical, radiographic, operative, postoperative, and functional outcomes were analyzed. Results A total of 22 patients (15 females, 7 males, average age 64.6 y) with isolated thoracic and thoracolumbar spine diseases were treated between 2005 and 2009. The indications for surgery included degenerative scoliosis (11), pathological fractures from tumors (2), adjacent level disease from prior fusions (5), thoracic disc herniations (3), and discitis/osteomyelitis (1). A total of 47 levels were treated. In the subset of patients treated for degenerative scoliosis, the mean preoperative and postoperative coronal Cobb angles were 22 and 14, respectively. The mean preoperative and postoperative sagittal angles were 39 and 44, respectively. The average estimated blood loss and length of stay were 227.5 mL and 4.8 d, respectively. Three complications consisting of wound infection, subsidence, and adjacent level disease requiring additional procedures were encountered. There were no neural, vascular, visceral injuries, or death. At a mean follow-up of 16.4 months (range, 3-50), we observed a 95.5% substantial clinical benefit. All patients who had reached a minimum of 6 months (95.5%) demonstrated radiographic evidence of fusion. Conclusions The XLIF technique can be expanded to treat diseases in the thoracic spine. Although the magnitude of deformity correction achieved is less than that of the traditional open approaches, the lesser invasiveness of this technique may be tolerable for the elderly and in patients with significant medical comorbidities.