Technical Note on the Role of Kambin's Triangle in the Evolution of Total Joint Replacement of the Lumbar Spine.

We provide a historical and technical perspective on the evolution of Kambin's triangle as a safe working corridor for percutaneous access to the intervertebral disc to an anatomically expanded space to accommodate and facilitate open lumbar total joint replacement. The nearly 6-decade progression from intradiscal access in the intact lumbar spine to an enlarged working space following facetectomy to accommodate a transforaminal lumbar interbody fusion, and eventual further expansion via pedicle vertebral body osteotomy to support motion preservation with total joint replacement, represents a unique evolutionary pathway in surgical technique development. For each of these steps in evolution, we detail and provide the historical context of the corresponding surgical modifications required to expand the original anatomical boundaries of Kambin's triangle. It is postulated that the introduction of machine learning technologies coupled with innovations in robotics, materials science, and advanced imaging will further accelerate and refine the adaptation of more complex, precise, and efficacious surgical procedures to treat spinal degeneration via this working corridor.

Are We Finally Ready for Total Joint Replacement of the Spine? An Extension of Charnley's Vision.

Professor Sir John Charnley has been rightfully hailed as a visionary innovator for conceiving, designing, and validating the Operation of the Century-the total hip arthroplasty. His groundbreaking achievement forever changed the orthopedic management of chronically painful and dysfunctional arthritic joints. However, the well-accepted surgical approach of completely removing the diseased joint and replacing it with a durable and anatomically based implant never translated to the treatment of the degenerated spine. Instead, decompression coupled with fusion evolved into the workhorse intervention. In this commentary, the authors explore the reasons why arthrodesis has remained the mainstay over arthroplasty in the field of spine surgery as well as discuss the potential shift in the paradigm when it comes to treating degenerative lumbar disease.

Loading of the lumbar spine during transition from standing to sitting: effect of fusion versus motion preservation at L4-L5 and L5-S1.

BACKGROUND CONTEXT: Transition from standing to sitting significantly decreases lumbar lordosis with the greatest lordosis-loss occurring at L4-S1. Fusing L4-S1 eliminates motion and thus the proximal mobile segments maybe recruited during transition from standing to sitting to compensate for the loss of L4-S1 mobility. This may subject proximal segments to supra-physiologic flexion loading. PURPOSE: Assess effects of instrumented fusion versus motion preservation at L4-L5 and L5-S1 on lumbar spine loads and proximal segment motions during transition from standing to sitting. STUDY DESIGN: Biomechanical study using human thoracolumbar spine specimens. METHODS: A novel laboratory model was used to simulate lumbosacral alignment changes caused by a person's transition from standing to sitting in eight T10-sacrum spine specimens. The sacrum was tilted in the sagittal plane while constraining anterior-posterior translation of T10. Continuous loading-data and segmental motion-data were collected over a range of sacral slope values, which represented transition from standing to different sitting postures. We compared different constructs involving fusions and motion preserving prostheses across L4-S1. RESULTS: After L4-S1 fusion, the sacrum could not be tilted as far posteriorly compared to the intact spine for the same applied moment (p<.001). For the same reduction in sacral slope, L4-S1 fusion induced 2.9 times the flexion moment in the lumbar spine and required 2.4 times the flexion motion of the proximal segments as the intact condition (p<.001). Conversely, motion preservation at L4-S1 restored lumbar spine loads and proximal segment motions to intact specimen levels during transition from standing to sitting. CONCLUSIONS: In general, sitting requires lower lumbar segments to undergo flexion, thereby increasing load on the lumbar disks. L4-S1 fusion induced greater moments and increased flexion of proximal segments to attain a comparable seated posture. Motion preservation using a total joint replacement prosthesis at L4-S1 restored the lumbar spine loads and proximal segment motion to intact specimen levels during transition from standing to sitting. CLINICAL SIGNIFICANCE: After L4-S1 fusion, increased proximal segment loading during sitting may cause discomfort in some patients and may lead to junctional breakdown over time. Preserving motion at L4-S1 may improve patient comfort and function during activities of daily living, and potentially decrease the need for adjacent level surgery.

Comparison of vertebroplasty and balloon kyphoplasty for treatment of vertebral compression fractures: a meta-analysis of the literature.

BACKGROUND CONTEXT: Previous investigators have reported on benefits and risks associated with vertebroplasty and kyphoplasty, but there are limited comparison data available. Additionally, much of the data is from retrospective studies and case series. PURPOSE: The purpose of this study is to review the literature and perform a meta-analysis of pain relief and risk of complications associated with vertebroplasty versus kyphoplasty. STUDY DESIGN: A meta-analysis of the literature on effectiveness of pain control and risk of complications after vertebroplasty versus balloon kyphoplasty. Outcomes measures include visual analog scale and complications. METHODS: A comprehensive review of the literature was performed. All studies providing information on pain relief and complications were included. Preoperative, postoperative, and change in visual analog scale (VAS) scores were tabulated. Data were analyzed to identify if a significant improvement in the VAS score occurred. Changes in the VAS scores were compared for vertebroplasty and kyphoplasty to determine if there was a significant difference. RESULTS: A total of 1,036 abstracts were identified. Of these, 168 studies met the inclusion criteria. Mean pre- and postoperative VAS scores for vertebroplasty were 8.36 and 2.68, respectively, with a mean change of 5.68 (p<.001). The mean pre- and postoperative VAS scores for kyphoplasty were 8.06 and 3.46, respectively, with a mean change of 4.60 (p<.001). There was statistically greater improvement found with vertebroplasty versus kyphoplasty (p<.001). The risk of new fracture was 17.9% with vertebroplasty versus 14.1% with kyphoplasty (p<.01). The risk of cement leak was 19.7% with vertebroplasty versus 7.0% with kyphoplasty (p<.001). CONCLUSIONS: Both vertebroplasty and kyphoplasty provided significant improvement in VAS pain scores. Vertebroplasty had a significantly greater improvement in pain scores but also had statistically greater risk of cement leakage and new fracture.

Minimally invasive lumbar spinal fusion.

Minimally invasive techniques for lumbar spine fusion have been developed in an attempt to decrease the complications related to traditional open exposures (eg, infection, wound healing problems). Anterior minimally invasive procedures include laparoscopic and mini-open anterior lumbar interbody fusion as well as the lateral transpsoas and percutaneous presacral approaches. Posterior techniques typically use a tubular retractor system that avoids the muscle stripping associated with open procedures. These techniques can be applied to both posterior and transforaminal lumbar interbody fusion procedures. Many initial reports have shown similar clinical results in terms of spinal fusion rates for both traditional open and minimally invasive posterior approaches. However, the anterior minimally invasive procedures are often associated with significantly greater incidence of complications and technical difficulty than their associated open approaches. There is a steep learning curve associated with minimally invasive techniques, and surgeons should not expect to master them in the first several cases.

Effect of lower two-level anterior cervical fusion on the superior adjacent level.

OBJECT: 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. METHODS: Five cadaveric cervical spine specimens were used in this study. The specimens were stabilized at T-1 and loaded at C-3 to 15 degrees flexion, 10 degrees extension, and 10 degrees 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. RESULTS: 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. CONCLUSIONS: 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.

Redundant publications in the orthopedic literature.

Rates of redundant publications in the general surgery literature are approximately 14%. This article identifies the rate of redundant publications in the orthopedic literature. All original articles published during the year 2000 in The Journal of Bone and Joint Surgery (American Volume), Journal of Orthopaedic Trauma, Journal of Spinal Disorders, and Spine were searched using PubMed. Redundancy rate was 4 (3.15%) of 127 for The Journal of Bone and Joint Surgery (American volume), zero (0%) of 70 for Journal of Orthopaedic Trauma, 2 (2.90%) of 69 for Journal of Spinal Disorders, and 11 (3.12%) of 353 for Spine.

Transforaminal lumbar interbody fusion: a retrospective study of long-term pain relief and fusion outcomes.

No long-term studies exist on the effectiveness of transforaminal lumbar interbody fusion. This study sought to determine postoperative pain, disability, and fusion status of transforaminal lumbar interbody fusion patients after > or = 4 years to establish long-term outcomes. A retrospective analysis of 42 patients with minimum 4-year follow-up was conducted. Patients completed visual analog pain scale (VAS) and Oswestry functional capacity evaluation pre- and postoperatively. Statistically significant improvement was noted in VAS and Oswestry functional capacity evaluation scores. Transforaminal lumbar interbody fusion is effective in alleviating intractable back pain over an extended time period. Solid radiographic fusion is unnecessary for clinically successful outcomes.

A comparison of outcomes of anterior cervical discectomy and fusion in patients with and without radicular symptoms.

Anterior cervical discectomy and fusion (ACDF) is commonly performed for degenerative conditions of the cervical spine with good to excellent results. There is controversy over the use of ACDF for patients with axial neck pain alone. A retrospective review of 202 patients from two private practice orthopaedic spine surgeons following ACDF with 39-month mean follow-up was performed. Patients completed pain drawings, pre- and postoperative visual analog pain scales (VAS), Oswestry functional capacity evaluations (OSW), and a postoperative neck disability index. Forty-one patients had axial neck pain alone, and 161 had radicular pain with or without neck pain. There were significant improvements in VAS and OSW scores following surgery for the combined study population as well as the neck pain only and radicular pain groups (p < .01). ACDF can be effectively used for treatment of patients with axial neck pain without radicular symptoms.

A treatment and outcomes analysis of patients with coccydynia.

BACKGROUND CONTEXT: Coccydynia is a painful condition of the terminal portion of the spine often resulting from direct trauma, childbirth or unknown etiology. This is a relatively rare condition with no universally accepted treatment protocol. PURPOSE: To more clearly determine the optimal treatment for patients with coccydynia and to assess the outcomes after conservative and surgical therapy. STUDY DESIGN: Retrospective review of outcomes of all patients presenting with symptoms of coccydynia during a 5-year period. PATIENT SAMPLE: Thirty-two patients presented to an orthopedic spine surgeon during a 5-year period with symptoms of coccydynia. OUTCOME MEASURES: Patients completed visual analog pain scales (VAS) and the Oswestry (OSW) functional capacity index. METHODS: Of the 32 patients in the study, 4 (13%) were treated with nonsteroidal anti-inflammatory drugs (NSAIDs) alone, 17 (53%) were treated with NSAIDs followed by local injections and 11 (34%) underwent coccygectomy after failure of NSAIDs and local injections. Patients completed VAS and OSW forms. Pain drawings were also completed. RESULTS: Patients undergoing surgery had significantly greater pretreatment VAS scores (8.3 vs 5.4, p=.002). Surgical patients also had greater OSW scores, but not significantly (36.6 vs 24.2, p=.223). Marked improvement was reported by 9 of 11 (82%) surgical patients. Three of 11 (27%) surgical patients developed wound infections and 1 (9%) wound dehiscence. All infections resolved following irrigation and debridement and a short course of oral antibiotics. CONCLUSIONS: Patients with coccydynia should be managed conservatively when possible. Treatment should include NSAIDs and local steroid injections. Patients will often require repeat injections over time. Surgery can offer reasonable results for patients failing conservative treatment, but they should be warned of the high rate of infection.

Use of electrical bone stimulation in spinal fusion.

Spinal fusion is commonly done to manage deformity, restore stability, and eliminate excessive motion at specific spinal levels. Pseudarthrosis limits the clinical success of spinal fusion. Three types of electrical stimulation, which is used to manage non-union in long bones, recently have been applied in an attempt to enhance the rate of spinal fusion. Direct current electrical stimulation is internal and thus eliminates dependence on patient compliance. Pulsed electromagnetic fields and capacitively coupled electrical stimulation are external techniques that require patient compliance but do not have the increased risk associated with implantable devices. Firm conclusions about efficacy are difficult to establish because of inconsistencies in both determining a reliable, reproducible end point for fusion and in incorporating the effect of patient parameters. Most data indicate a positive effect for use of direct current stimulation, but further studies are necessary to determine its appropriateness as an adjuvant to spinal fusion.

Vertebroplasty: a new treatment strategy for osteoporotic compression fractures.

Vertebroplasty is a procedure in which bone cement is injected into a fractured vertebral body in an attempt to stabilize fractured segments and reduce pain. This procedure was originally used to treat spinal lesions caused by metastases and has recently been used to treat severe bone loss caused by osteoporosis. In this article, we review the current treatment for osteoporosis, introduce vertebroplasty with its associated efficacy and risks, and describe kyphoplasty.

Dysphagia caused by anterior cervical osteophytes: a case report.

This 79-year-old man had a several-year history of dysphagia. On presentation, he spoke with difficulty but was not short of breath, and hemoptysis was present. A 17-mm osteophyte anterior to C3-C4 encroached on the posterior aspect of the oral pharynx and esophagus. The patient underwent C3-C6 anterior ostectomy; recovery was complete within 4 weeks.

Preliminary experience with a new surgical treatment for dysphagia due to anterior cervical osteophytes.

A technique for surgical treatment of anterior cervical osteophytes is presented. A midline trough is created in the osteophytes using a burr under fluoroscopy down to the anterior cervical line. A rongeur is used to remove the remaining osteophytes while protecting the lateral soft tissues. Two patients presented with symptoms of progressive dysphagia secondary to anterior cervical osteophytes. Each underwent surgical ostectomy without complication after failing conservative treatment. This technique provides a safe, effective method to remove anterior cervical osteophytes.

Questionnaire survey of spine surgeons on the use of methylprednisolone for acute spinal cord injury.

STUDY DESIGN: A questionnaire survey. OBJECTIVE: Estimate the use and justification of the steroid protocol for spinal cord injury (SCI) patients. SUMMARY OF BACKGROUND DATA: There remains significant debate over clinical benefits and potential complications of the steroid protocol for SCI patients. METHODS: A survey was sent to spine surgeons requesting information on 1) specialization, 2) trauma center affiliation, 3) use of steroid protocol, 4) justification of using steroid protocol, and 5) SCI volume. RESULTS: Responses were received from 305 surgeons. Fourteen (4.6%) surgeons used steroids only if initiated before their consult, 262 (85.9%) would initiate if within the accepted 8-hour timeframe, 20 (6.6%) did not use steroids at all, and 9 (3.0%) used a different protocol. Justification for steroids use: 65 improved recovery, 64 institutional protocol, 110 medicolegal reasons, and 26 did not personally initiate steroids. Eighteen surgeons listed both clinical benefit and institutional protocol, and 22 others listed both institutional protocol and medicolegal reasons. CONCLUSIONS: The majority (90.5%) of responding surgeons used the steroid protocol; however, only 24.1% used the steroid protocol due to a belief in improved clinical outcomes.

Neuroimaging in low back pain.

Patients commonly present to family physicians with low back pain. Because the majority of patients fully or partially recover within six weeks, imaging studies are generally not recommended in the first month of acute low back pain. Exceptions include patients with suspected cauda equina syndrome, infection, tumor, fracture, or progressive neurologic deficit. Patients who do not improve within one month should obtain magnetic resonance imaging if a herniated disc is suspected. Computed tomographic scanning is useful in demonstrating osseous structures and their relations to the neural canal, and for assessment of fractures. Bone scans can be used to determine the extent of metastatic disease throughout the skeletal system. All imaging results should be correlated with the patient's signs and symptoms because of the high rate of positive imaging findings in asymptomatic persons.

Effect of spirituality on successful recovery from spinal surgery.

BACKGROUND: Many patients believe prayer helps them recover from health problems. Benefits of spirituality on other illnesses and surgical procedures have been reported. It is unknown whether patients with strong spiritual beliefs have a greater propensity for successful recovery from spinal surgery. METHODS: In this study, 188 patients having spinal surgery completed the visual analog pain scale (VAS) and the Oswestry functional capacity questionnaire (OSW) before and after operation, and the scores were used to assess surgical outcome. Degree of spirituality was assessed using the INSPIRIT survey. RESULTS: Paired t test revealed significant improvements in both the VAS and OSW outcome measures. Linear regression analysis revealed no correlation between change in either VAS or OSW. CONCLUSIONS: These results suggest that recovery from spinal surgery may be more dependent on proper patient selection and surgical technique than on patient spiritual beliefs.

Biomechanical study on the effect of cervical spine fusion on adjacent-level intradiscal pressure and segmental motion.

STUDY DESIGN: A biomechanical study was performed using cadaveric cervical spine specimens. OBJECTIVE: To determine the effect of cervical spine fusion on adjacent-level intradiscal pressure. SUMMARY OF BACKGROUND DATA: Clinical studies have reported that patients with spinal fusion are at greater risk of pathology and early disc degeneration at adjacent levels. It is hypothesized that eliminating motion at one level leads to hypermobility and increased forces at adjacent levels, thus increasing the rate of disc degeneration. METHODS: Six cadaveric cervical spine specimens were tested. Specimens were stabilized at T1 and loaded at C3 to 20 degrees of flexion and 15 degrees of extension. Intradiscal pressures and segmental motion at C4-C5 and C6-C7 were recorded first on intact specimens, and then after anterior cervical plating at C5-C6. Changes in intradiscal pressure and segmental motion were calculated and statistically analyzed using a paired Student t test. RESULTS: Intradiscal pressures were significantly increased during flexion at both adjacent levels. The pressure increased by 73.2% at C4-C5 (P = 0.002), and by 45.3% at C6-C7 (P = 0.006). Intradiscal pressures increased at both adjacent levels during extension, but not significantly. During flexion, segmental motion increased at both adjacent levels, with greater increases at C4-C5. During extension, segmental motion increased at both adjacent levels, with greater increases at C6-C7. CONCLUSIONS: Clinical studies have reported increased rates of disc degeneration at levels adjacent to fusion. It is believed that eliminating motion through fusion shifts the load to the adjacent levels, causing earlier disc degeneration. This study has shown that significant increases in intradiscal pressure and segmental motion occur at levels adjacent to fusion during normal range of motion. These results may partially explain the mechanism of early disc degeneration at levels adjacent to cervical spine fusion.

A modified technique for anterior multilevel cervical fusion.

Anterior cervical fusion with interbody bone graft and anterior plating is commonly performed. Unfortunately, the plate has been reported to shield the graft from loading, thus reducing fusion rates. Interbody fusion cages have been effective in the lumbar spine and have gained acceptance in the cervical spine. Twenty-five patients underwent anterior cervical fusion with this modified technique. All patients received anterior diskectomy and corpectomy, placement of an interbody fusion cage packed with corpectomy bone, and application of an anterior cervical plate. Fusion was defined by radiographic evidence of trabecular bone bridging through the cage. No external bracing was used except soft collars as needed. Pre- and postoperative pain scales were completed and statistically analyzed using paired t tests. There were no cases of pseudoarthrosis or major neurological, vascular, or wound complications. There was one case of mild dysphagia that remained unresolved. Mean operative time was comparable to standard instrumented multilevel cervical fusion surgeries. Visual analogue pain scales were significantly improved following surgery. The advantages of using interbody cages with anterior plating include immediate stability and support, elimination of donor site pain from iliac crest bone autograft, and a decrease in pseudoarthrosis by halving the number of fusion surfaces.