An updated classification of the anatomical variations of the internal iliac venous drainage system: Surgical implications for anterior lumbar spinal approaches.

BACKGROUND: Advanced pelvic surgery is associated with potential vascular risks. The aim of this study was to complete the existing classification of the anatomical variations of the internal iliac veins encountered on a series of preoperative angio CT with a view to performing anterior lumbar spine surgery. MATERIALS AND METHODS: In this monocentric retrospective study conducted between 2010 and 2020, all preoperative angio CT performed before an anterior lumbar surgery were systematically analyzed. All the abnormalities of the iliac veins were referenced in an updated classification system. RESULTS: 910 patients (431 men and 479 women) with a mean age of 49 years [16-88] were included. Apart from the most common variant in the population (type I), 64 anatomical variations (7.0%) in the iliac veins were reported and classified according to our new classification. The percentage of coverage of the L4-L5 intervertebral disc is 52%, including 32% by the inferior vena cava before the confluence of the common iliac veins. At the level of the L5-S1 intervertebral disc, the coverage is 30% (same distribution between left and right). CONCLUSIONS: Variations of the iliac veins are frequent, and contrary to what one might think, and even if they can represent an anatomical trap during surgery, certain variations do not limit anterior lumbar spine surgery and are not more associated with vascular complications. Nevertheless, these anatomical variations must be known before any advanced pelvic surgery. Depending on their distribution, level L5-S1 is more suitable for ALIF, level L4-L5 for OLIF approaches.

The proximal femur fracture epidemic continued during the COVID-19 pandemic: Results of an observational study.

INTRODUCTION: The aim of this study was to compare the volume and characteristics of emergency trauma surgery procedures done at our hospital between March 20 and April 20, 2020 (the first month of the national lockdown in France) and to compare these data to the same period in 2019. We hypothesized that a portion of fractures are unavoidable, thus specific preventative measures will be needed to reduce their incidence. METHODS: This was a continuous, observational and single center study. All patients who required urgent surgery for a fracture between March 20 and April 20, 2020, were included. Data for the same period in 2019 was retrieved. All the procedures were done at our hospital, which is a regional level II trauma center. RESULTS: During the first month of the lockdown, 70 patients underwent emergency surgery because of a fracture, versus 109 patients in the same period in 2019, thus an overall 36% drop. The mean age of the patients was higher in 2020 (68.4 years SD=22) than in 2019 (60.3 years SD=24, p=0.0210). There were fewer recreational and motor vehicle accidents in 2020 (34 vs. 10) and fewer work-related accidents (7 vs. 2) although the number of accidents at home were similar (65 vs. 55). CONCLUSION: During a public health emergency, it is vital to continue doing trauma surgery procedures, even though it requires a specific care pathway. The lockdown and associated behavioral changes have altered the spectrum of trauma surgery. A major decrease in motor vehicle, recreation and work-related accidents is the avoidable portion of this surgical activity, justifying specific preventative measures during a public health crisis. Conversely, the incidence of geriatric fractures - particularly of the proximal femur - did not change much overall, thus there is need for additional preventative measures in these patients. LEVEL OF EVIDENCE: V, observational study.

Minimally invasive triangular lumboiliac and iliosacral fixation of posterior pelvic ring injuries with vertical instability: Technical note.

To date, no strong consensus exists on the best way to treat posterior pelvic ring injuries when there is no neurological deficit. Various fixation methods have been described; more recently, constructs that combine lumboiliac and iliosacral fixation have been introduced. This type of fixation is mainly indicated in cases of spinopelvic dissociation with large displacement of fracture fragments in the sagittal plane. However, these techniques are associated with postoperative complications, particularly infections and severe skin complications. This led us to propose a minimally invasive lumboiliac and iliosacral fixation technique for posterior pelvic ring injuries. The procedure is done with the patient prone. It consists of pedicle screw insertion into L4 or L5 and screw fixation of the ilium with fluoroscopy guidance; intraoperative distraction can be done depending on the amount of displacement. An iliosacral screw is then inserted percutaneously to allow reduction in the transverse plane and yield a triangular construct. In the five patients that we have operated using this technique, the mean preoperative vertical displacement was 11.9±6.9mm (SD) (min 1.3, max 19.7) versus 3.7±3.2mm (min 0.3, max 6.7) postoperatively and the mean preoperative frontal displacement was 7.5±3.7mm (min 4.2, max 12.4) versus 2.5±2.0mm (min 0.3, max 4.3) postoperatively. Minimally invasive iliosacral and lumboiliac fixation is an option for treating posterior pelvic ring fractures free of neurological deficit and especially spinopelvic dissociation.

Sagittal reduction of spinal deformity: Superior versus lateral screw-rod connection.

INTRODUCTION: Spinal malalignment can greatly impact a patient's quality of life. Various sagittal parameters are used as realignment goals; however, about 50% of patients end up being under-corrected postoperatively. To improve the correction, prebent rods are available with a radius of curvature corresponding to the patient's "ideal" sagittal alignment. But no studies have been done on how the radius of curvature changes according to the type of connection between the pedicle screws and rods. The goal of this experimental study was to quantify how much prebent rods flatten based on the method used to connect the screw and rod: top-loading screw vs. dome screw with lateral connector. METHODS: The experiment was done on a material testing system in axial compression on three constructs consisting of two rods secured with top-loading screws and three other constructs consisting of two rods secured with dome screws and lateral connector. The maximum angle of the construct was measured during loading and after removing the load. The primary outcome measure was the mean angle in each construct at each step. RESULTS: The mean angle of the constructs with top-loading screws when subjected to 500 N load was significantly less than in the constructs with dome screws and lateral connector: 18.6° vs. 24.5° respectively (p<0.0003). The mean angle of the constructs with top-loading screws after removing the load was significantly less than in the constructs with dome screws and lateral connector: 25.7° vs. 32.3° respectively, (p<0.0005). CONCLUSION: In vitro, top-loading screws produced significantly greater flattening than dome screws with lateral connector. These findings must be confirmed in vivo. Understanding the behavior of rods as a function of the type of screw connection can be an important factor to minimize the risk of under-correction in the sagittal plane. LEVEL OF EVIDENCE: III.

Treatment of osteoporotic vertebral fractures.

Osteoporosis is a public health problem that is contributing to an increasing number of osteoporotic vertebral fractures. The aim of this lecture is to summarize the current state of knowledge about osteoporotic fractures by answering five questions. 1/How does the spine typically age and how is osteoporosis diagnosed? Various normal aging processes will gradually modify the vertebral column (static, dynamic, bone quality). Osteoporosis is diagnosed through a DEXA scan. 2/How is an osteoporotic fracture evaluated clinically and radiologically? Magnetic resonance imaging is the preferred modality for making the diagnosis and selecting the most appropriate treatment. 3/What are the treatment options for an osteoporotic fracture? The options are conservative treatment, conventional surgery, and minimally invasive techniques (cementoplasty, percutaneous instrumentation). 4/Which fractures should be treated, and which technique should be used? The choice is clear when neurological deficits are present, although the indications are less firm when there is no deficit. The treatment can be conservative (back brace) if the fracture is non-displaced and minimally painful, vertebroplasty if the fracture is painful and shows hyperintensity on T2-STIR sequences, vertebral expansion if the radiological deformity worsens along with symptoms. 5/What are the technical challenges and complications related to the presence of osteoporosis when treating vertebral fractures surgically? The reduced bone stock increases the risk of poor implant hold and postoperative mechanical complications (adjacent fracture, junctional kyphosis). Technical solutions have been developed (augmented screw fixation, transitional zone) to limit their impact. It is essential to know and master these techniques, and their indications. Treatment of the osteoporosis itself is crucial. Level of evidence V; Expert opinion.

Sacral hiatus corticosteroid injection in the management of radicular pain in adults.

Radicular pain is a common reason for patients to consult at back pain clinics. While epidural steroid injections are widely done, some aspects are still controversial. The epidural space can be accessed via a transforaminal approach, an interlaminar route or by passing through the sacral hiatus. The aim of this article is to describe the epidural injection technique through the sacral hiatus that our team uses and to report our experience with it. Beyond the treatment effect, sacral hiatus corticosteroid injection can be useful as a diagnostic test or as an interim solution. Image-guided injection is recommended to ensure optimal positioning of the needle below S3. Sacral hiatus corticosteroid injection is a relevant alternative for treating lumbar radiculopathy in adults.

French Spine Surgery Society guidelines for management of spinal surgeries during COVID-19 pandemic.

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019 in China, various measures have been adopted in order to attenuate the impact of the virus on the population. With regard to spine surgery, French physicians are devoted to take place in the national plan against COVID-19, the French Spine Surgery Society therefore decided to elaborate specific guidelines for management of spinal disorders during COVID-19 pandemic in order to prioritize management of patients. A three levels stratification was elaborated with Level I: Urgent surgical indications, Level II: Surgical indications associated to a potential loss of chance for the patient and Level III: Non-urgent surgical indications. We also report French experience in a COVID-19 cluster region illustrated by two clinical cases. We hope that the guidelines formulated by the French Spine Surgery Society and the experience of spine surgeons from a cluster region will be helpful in order optimizing the management of patients with urgent spinal conditions during the pandemic.

"Patient-specific" rods in the management of adult spinal deformity. One-year radiographic results of a prospective study about 86 patients.

INTRODUCTION: Based on global knowledge regarding sagittal alignment, preoperative planning is a crucial point in the management of adult spinal deformity (ASD). Patient-specific rods (PSR) have been recently developed in order to change preoperative planning into a postoperative reality. The aim of this study was therefore to analyze the 1-year radiographic results of prospective ASD cohorts managed using PSR. METHODS: In this prospective study, all patients managed for an ASD using PSR since 2014 and with a minimal follow-up of 1-year were included. Radiographic parameters were evaluated pre and postoperatively and patients were stratified according to their final sagittal alignment status (A: aligned vs. MA: malaligned) according to the age-related Schwab classification. Statistical analyses were performed using the Student's-t-test in order to compare groups. RESULTS: Eighty-six patients were included in the study, with a mean age of 57.2 years. At one-year follow-up, mean sagittal vertical axis and pelvic incidence-lumbar lordosis mismatch were significantly improved. Twenty-two patients were aligned on both sagittal and coronal planes, 52 patients were still considered as malaligned in the sagittal plane, 3 were still malaligned in the coronal plane and 9 patients were malaligned in both planes (vs. 42 patients preoperatively). At final follow-up, the rate of mechanical complications was 18%. CONCLUSION: Based on our results, patient-specific rods can represent a useful supplementary tool in the management of ASD and transform preoperative planning into a postoperative reality. Corrections rates are comparable to other series in the literature with conventional rods, and fewer complications have been reported. However, further studies will be required in order to confirm these results.

Surgeon's and patient's radiation exposure during percutaneous thoraco-lumbar pedicle screw fixation: A prospective multicenter study of 100 cases.

HYPOTHESIS: Percutaneous pedicle screw fixations (PPSF) are increasingly used in spine surgery, minimizing morbidity through less muscle breakdown but at the cost of intraoperative fluoroscopic guidance that generates high radiation exposure. Few studies have been conducted to measure them accurately. MATERIAL AND METHODS: The objective of our study is to quantify, during a PPSF carried out in different experimented centers respecting current radiation protection recommendations, this irradiation at the level of the surgeon and the patient. We have prospectively included 100 FPVP procedures for which we have collected radiation doses from the main operator. For each procedure, the doses of whole-body radiation, lens and extremities were measured. RESULTS: Our results show a mean whole body, extremity and lens exposure dose per procedure reaching 1.7±2.8µSv, 204.7±260.9µSv and 30.5±25.9µSv, respectively. According to these values, the exposure of the surgeon's extremities and lens will exceed the annual limit allowed by the International Commission on Radiological Protection (ICRP) after 2440 and 4840 procedures respectively. CONCLUSION: Recent European guidelines will reduce the maximum annual exposure dose from 150 to 20mSv. The number of surgical procedures to not reach the eye threshold, according to our results, should not exceed 645 procedures per year. Pending the democratization of neuronavigation systems, the use of conventional fluoroscopy exposes the eyes in the first place. Therefore they must be protected by leaded glasses. LEVEL OF PROOF: IV, case series.

The comprehensive anatomical spinal osteotomy classification.

BACKGROUND: Global sagittal malalignment is significantly correlated with health-related quality-of-life scores in the setting of spinal deformity. In order to address rigid deformity patterns, the use of spinal osteotomies has seen a substantial increase. Unfortunately, variations of established techniques and hybrid combinations of osteotomies have made comparisons of outcomes difficult. OBJECTIVE: To propose a classification system of anatomically-based spinal osteotomies and provide a common language among spine specialists. METHODS: The proposed classification system is based on 6 anatomic grades of resection (1 through 6) corresponding to the extent of bone resection and increasing degree of destabilizing potential. In addition, a surgical approach modifier is added (posterior approach or combined anterior and posterior approaches). Reliability of the classification system was evaluated by an analysis of 16 clinical cases, rated 2 times by 8 different readers, and calculation of Fleiss kappa coefficients. RESULTS: Intraobserver reliability was classified as 'almost perfect'; Fleiss kappa coefficient averaged 0.96 (range, 0.92-1.0) for resection type and 0.90 (0.71-1.0) for the approach modifier. Results from the interobserver reliability for the classification were 0.96 for resection type and 0.88 for the approach modifier. CONCLUSION: This proposed anatomically based classification system provides a consistent description of the various osteotomies performed in spinal deformity correction surgery. The reliability study confirmed that the classification is simple and consistent. Further development of its use will provide a common frame for osteotomy assessment and permit comparative analysis of different treatments.

The comprehensive anatomical spinal osteotomy classification.

BACKGROUND: Global sagittal malalignment is significantly correlated with health-related quality-of-life scores in the setting of spinal deformity. In order to address rigid deformity patterns, the use of spinal osteotomies has seen a substantial increase. Unfortunately, variations of established techniques and hybrid combinations of osteotomies have made comparisons of outcomes difficult. OBJECTIVE: To propose a classification system of anatomically-based spinal osteotomies and provide a common language among spine specialists. METHODS: The proposed classification system is based on 6 anatomic grades of resection (1 through 6) corresponding to the extent of bone resection and increasing degree of destabilizing potential. In addition, a surgical approach modifier is added (posterior approach or combined anterior and posterior approaches). Reliability of the classification system was evaluated by an analysis of 16 clinical cases, rated 2 times by 8 different readers, and calculation of Fleiss kappa coefficients. RESULTS: Intraobserver reliability was classified as "almost perfect"; Fleiss kappa coefficient averaged 0.96 (range, 0.92-1.0) for resection type and 0.90 (0.71-1.0) for the approach modifier. Results from the interobserver reliability for the classification were 0.96 for resection type and 0.88 for the approach modifier. CONCLUSION: This proposed anatomically based classification system provides a consistent description of the various osteotomies performed in spinal deformity correction surgery. The reliability study confirmed that the classification is simple and consistent. Further development of its use will provide a common frame for osteotomy assessment and permit comparative analysis of different treatments.

Salvage of lumbar pseudarthrosis with customized large-diameter pedicle screws: report of two cases.

STUDY DESIGN: A report of two cases using custom-manufactured pedicle screws for revision spinal arthrodesis for pseudarthrosis in the setting of widely dilated pedicle screw tracts. OBJECTIVE: To present surgical outcomes of a previously unreported treatment for pseudarthrosis with widely dilated pedicle screw tracts. SUMMARY OF BACKGROUND DATA: Techniques for revision of lumbar pseudarthrosis with severe screw loosening and widely dilated pedicle screw tracts represent a challenging clinical scenario. If stable fixation cannot be achieved, fixation may fail or adjacent normal levels may need to be included in the construct. METHODS: Two patients presenting with painful pseudarthrosis after lumbar spinal fusion and instrumentation loosening with widely dilated pedicle screw tracts were treated with revision anterior and posterior spinal fusion using custom-manufactured large-diameter pedicle screws. RESULTS: In both cases, the custom-manufactured pedicle screws achieved excellent purchase in the dilated pedicle screw tract. Both patients went on to solid fusion at 1 year after surgery. CONCLUSION: This is a previously unreported technique for revision spinal fusion in the setting of loose instrumentation with widely dilated pedicle screw tracts.

Systems for long-segment percutaneous spinal fixation: technical feasibility for various indications.

SUMMARY OF BACKGROUND DATA: New methods of spinal percutaneous fixation are developing very rapidly. However, few studies to date have focused on long-segment methods of instrumentation. OBJECTIVE: To report the technical feasibility of long-segment percutaneous stabilization for various indications. METHODS: The study included 24 patients with a mean age of 58 years (range 38-79). The etiologies included trauma, infection, tumors, or pathology secondary to degenerative lumbar scoliosis. The damaged vertebrae ranged from T5 to L4. All of the patients underwent posterior percutaneous long-segment fixation. When necessary, the anterior spinal column was stabilized by balloon kyphoplasty or via anterior approach. The results obtained were analyzed on the basis of clinical and radiological criteria. RESULTS: The constructs involved four levels on average per patient, located between T3 and S1. No extra-pedicular misplacements were observed. Two technical difficulties were noticed without clinical consequences. A significant improvement in the pain levels was obtained in all the patients in this series. CONCLUSIONS: Long-segment percutaneous fixation was found to be technically feasible and to considerably improve the patients' spinal deformations. When associated with balloon kyphoplasty, this intervention seems to provide less loss of correction than previous methods, and posterior fusion was therefore not required. As with all new methods, there is a learning curve, and the indications have to be strictly observed. Further studies need to be performed, however, with a longer follow-up to confirm the absence of long-term complications.

Accessory iliac vein: surgical implications.

BACKGROUND: One of the main difficulties in using an anterior retroperitoneal approach in prosthetic lumbar disk replacement surgery is the exposure of the anterior aspect of the spine because of the risk of hemorrhage because of vascular injury when the venous structures are mobilized. PURPOSE: The goal of our study was to use computed tomography (CT) to research for anatomic variations of the ileocaval drainage network, which were likely to complicate this type of procedure. DESIGN: Prospective study. PATIENT SAMPLE: Ninety patients (48 males, 42 females) explored between July 2003 and February 2007. OUTCOME MEASURES: Not applicable. METHODS: All the patients had a CT scan before disk replacement surgery to treat degenerative lumbar disk disease by a microinvasive, anterior retroperitoneal approach. RESULTS: Eighteen of 90 patients presented with variations in their iliocaval drainage network: 3 cases of double inferior vena cava, 1 case of duplication of the inferior vena cava, 5 cases of ectopic internal iliac veins, 9 cases of accessory iliac veins. CONCLUSIONS: Anatomical variations in the iliocaval venous drainage system are fairly frequent but easy to analyze by CT. Even if they have no functional impact, they must be analyzed and described because they can be of great interest in the preoperative workup for retroperitoneal lumbar surgery.

Lumbar total disc replacement. Surgical technique.

BACKGROUND: Symptomatic lumbar degenerative disc disease is a challenging entity to treat. The results of arthrodesis may be compromised in the short term by pseudarthrosis and in the long term by pain at the iliac-crest donor site and by junctional degeneration. Total disc replacement has the potential to provide long-lasting relief to these patients. The purpose of this study was to present the clinical and radiographic results assessed seven to eleven years following a Prodisc total lumbar disc replacement. METHODS: Sixty-four patients had single or multiple-level implantation of a total lumbar disc replacement between 1990 and 1993. The mean duration of follow-up was 8.7 years. Clinical results were evaluated by assessing preoperative and postoperative lumbar pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Preoperative and post-operative radiographs were evaluated by assessing preoperative and postoperative lumbar pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Preoperative and post-operative radiographs were evaluated as well. Subgroup analysis was performed to determine if gender, an age of less than forty-five years, previous surgery, or multilevel surgery had an effect on outcome. RESULTS: At an average of 8.7 years post-operatively, there were significant improvements in the backpain, radiculopathy, disability, and modified Stauffer-Coventry scores. Thirty-three of the fifty-five patients with sufficient follow-up had an excellent result, eight had a good result, and fourteen had a poor result. Neither gender nor multilevel surgery affected outcome. An age of less than forty-five years and prior lumbar surgery had small but significant negative effects on outcome. Radiographs did not demonstrate loosening, migration, or mechanical failure in any patient. Five patients had approach-related complications. CONCLUSIONS: The Prodisc lumbar total disc replacement appears to be effective and safe for the treatment of symptomatic degenerative disc disease. Gender and multilevel surgery did not affect the outcomes, whereas prior lumbar surgery or an age of less than forty-five years was associated with slightly worse outcomes. Longer follow-up of this cohort of patients and randomized trials comparing disc replacement with arthrodesis are needed.

Lumbar total disc replacement. Seven to eleven-year follow-up.

BACKGROUND: Symptomatic lumbar degenerative disc disease is a challenging entity to treat. The results of arthrodesis may be compromised in the short term by pseudarthrosis and in the long term by pain at the iliac-crest donor site and by junctional degeneration. Total disc replacement has the potential to provide long-lasting relief to these patients. The purpose of this study was to present the clinical and radiographic results assessed seven to eleven years following a Prodisc total lumbar disc replacement. METHODS: Sixty-four patients had single or multiple-level implantation of a total lumbar disc replacement between 1990 and 1993. The mean duration of follow-up was 8.7 years. Clinical results were evaluated by assessing preoperative and postoperative lumbar pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Preoperative and postoperative radiographs were evaluated as well. Subgroup analysis was performed to determine if gender, an age of less than forty-five years, previous surgery, or multilevel surgery had an effect on outcome. RESULTS: At an average of 8.7 years postoperatively, there were significant improvements in the back-pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Thirty-three of the fifty-five patients with sufficient follow-up had an excellent result, eight had a good result, and fourteen had a poor result. Neither gender nor multilevel surgery affected outcome. An age of less than forty-five years and prior lumbar surgery had small but significant negative effects on outcome. Radiographs did not demonstrate loosening, migration, or mechanical failure in any patient. Five patients had approach-related complications. CONCLUSIONS: The Prodisc lumbar total disc replacement appears to be effective and safe for the treatment of symptomatic degenerative disc disease. Gender and multilevel surgery did not affect the outcomes, whereas prior lumbar surgery or an age of less than forty-five years was associated with slightly worse outcomes. Longer follow-up of this cohort of patients and randomized trials comparing disc replacement with arthrodesis are needed.

Functional and radiographic outcome of thoracolumbar and lumbar burst fractures managed by closed orthopaedic reduction and casting.

STUDY DESIGN: Retrospective review. OBJECTIVES: To determine clinical and radiographic outcomes of thoracolumbar and lumbar burst fractures without neurologic injury treated by closed reduction and casting. Patient factors associated with poor outcome are identified. SUMMARY OF BACKGROUND DATA: The results of ambulatory bracing, surgery, and prolonged recumbency for burst fractures have been reported. There are no reports of results of closed reduction and casting. METHODS: Retrospective review of 41 neurologically intact patients with thoracolumbar and lumbar burst fractures was performed. Four patients with neurologic injury who refused surgery were included, for a total of 45 patients. All patients had closed reduction and casting. Functional, pain, and employment status were assessed using the Denis system. Neurologic function was graded using the Frankel scale. Radiographic evaluation of vertebral kyphosis, regional kyphosis, anterior body compression, and sagittal index were performed at time of injury, postreduction, 4 months, and final follow-up. RESULTS: Sixty-four percent of patients had minimal or no pain. Eight percent had constant, severe pain. At time of injury, 71% of patients were employed. At 8-month follow-up, 58% of patients were employed. Closed reduction resulted in significant correction of vertebral wedging from a mean of 15 degrees to 5 degrees. Deformity tended to recur by 4 months, but the degree of residual deformity appears to be less than that reported in other series. No complications resulted from the fracture reduction procedure. CONCLUSIONS: Closed reduction and casting of thoracolumbar and lumbar burst fractures is a safe treatment method that yields acceptable functional and radiographic results.

Long-term flexion-extension range of motion of the prodisc total disc replacement.

The rationale for total disc replacement is avoidance of the junctional degeneration seen after arthrodesis by preservation of segmental motion. To justify the use of disc prostheses, it is essential to document maintained range of motion (ROM) and sagittal alignment at long-term follow-up. This is a retrospective radiographic study of 42 patients who had placement of 58 first-generation Prodisc prostheses at a mean follow-up of 8.7 years. Flexion-extension ROM was measured by Cobb's method. Junctional levels were evaluated for junctional degeneration. Pre- and postoperative global and segmental lordosis were measured. Prognostic patient factors predicting ROM of <2 degrees were evaluated. We observed ROM of at least 2 degrees in 66% of Prodisc prostheses at 8.7-year follow-up, although ROM was less than that reported in asymptomatic normal individuals. Mean ROM for disc prostheses with motion was 7.5 degrees at L3-L4, 6.2 degrees at L4-L5, and 4.1 degrees at L5-S1. Mean ROM for all prostheses was 3.8 degrees. The incidence of radiographic junctional degeneration was 24%, although no patients required surgery for symptomatic junctional degeneration. Mean ROM of prostheses below a degenerated junctional disc was 1.6 degrees compared with 4.7 degrees below a normal junctional disc (P < 0.035). Females were 3.5 times more likely to have ROM of <2 degrees. This is the longest published follow-up study of a lumbar disc replacement. The data show that ROM is preserved at long-term follow-up in the majority of patients. Global and segmental sagittal alignment improve after surgery. Furthermore, there is an association between ROM of disc prostheses and the development of junctional degeneration.

Lumbar disc replacement: preliminary results with ProDisc II after a minimum follow-up period of 1 year.

Total disc replacement has the potential to replace fusion as the gold standard surgical treatment of degenerative disc disease. Potential advantages of disc replacement over fusion include avoidance of pseudarthrosis, postoperative orthoses, and junctional degeneration. After observing satisfactory clinical results at 7-11 years' follow-up with the ProDisc first-generation implant, a second-generation prosthesis was designed. This study is a prospective analysis of the early results of total disc replacement with the ProDisc II total disc prosthesis. Fifty-three patients had single-level or multilevel disc replacement and were evaluated clinically and radiographically preoperatively and at mean 1.4-year follow-up. There were clinically and statistically significant improvements in back and leg pain Visual Analog Scale and Oswestry disability scores that were maintained at final follow-up. The clinical results of patients with single- and multilevel surgery were equivalent. Satisfactory results were achieved in 90% of patients who had previous lumbar surgery. Complications occurred in 9% of patients and included vertebral body fracture, transient radicular pain, implant malposition, and transient retrograde ejaculation. Three patients (6%) required reoperation to address complications. No mechanical failure of the implants or loosening was observed, and the prostheses retained motion. Randomized, prospective, long-term studies will be necessary to compare the effectiveness of arthrodesis with total disc replacement.