Is Minimally Invasive Bipolar Technique a Better Alternative to Long Fusion for Adult Neuromuscular Scoliosis?

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To report the results for an alternative technique based on minimally invasive fusion-less surgery. This approach is original in that it corrects deformities by proximal and distal fixation, with reliable pelvic fixation through the use of iliosacral screws on osteoporotic bones. METHODS: Adult cerebral palsy patients requiring spinal correction surgery were included prospectively between 2015 and 2019. The technique involved the use of a double-rod construct anchored proximally by four clawed hooks and distally by iliosacral screws, in a minimally invasive approach. Cobb angle and pelvic obliquity were measured before and after initial surgery and at final follow-up. Complications and functional results were reviewed. This group (P) was compared with a second group (R) of patients who underwent surgery between 2005 and 2015, for whom data were collected retrospectively. RESULTS: Thirty-one patients were included in group P, and 15 in group R. The two groups were comparable for demographic data and deformity. At most recent follow-up (3 years for group P [2-6] and 5 years for group R [2-16]), neither correction nor surgical complications differed between the two groups. However, group P had 50% less blood loss and a lower medical complication rate than group R. CONCLUSIONS: Our results confirm the effectiveness of this minimally invasive technique for neuromuscular scoliosis in adults. The results were similar to those obtained with the usual techniques, but with fewer medical complications. Confirmation of these results is now required for a longer follow-up period.

Pre- and postoperative MRI analysis of central decompression in MIS fusion with lumbar stenosis.

OBJECTIVES: Mini-invasive approaches have grown substantially these last decades in spinal surgery, notably for lumbar decompressions and fusion, with advantages over open approaches in terms of morbidity reduction. However, to our knowledge, no study has measured on MRI the amount of central decompression obtained by MIS approach. The goal of this study was to precisely measure the decompression of central stenosis by unilateral MIS approaches. METHODS: The files of 42 patients that had a MIS lumbar fusion with central decompression for central stenosis were reviewed. All patients had a pre- and postoperative MRI that allowed on T2 axial images to classify the central stenosis, according to Schizas' classification, and measure the dural sac cross-sectional area (DSCA) and the anteroposterior diameter (DAP). The statistical analysis was made with paired t-test. RESULTS: Fifty-six levels were analyzed, mostly L4L5 (58%). The mean preoperative DSCA was 70.53mm2 and the mean postoperative DSCA was 172.2mm2. The mean preoperative DAP was 6.15mm and postoperative was 10.68mm. Preoperatively, the levels analyzed were rated B, C or D according to Schizas for 53 out of 56 levels and A1-4 for 51 out of 56 levels in postoperative. All the results were statistically significant (p<0.001). CONCLUSION: Decompression, assessed by MRI, seems to be equivalent by MIS approach to open laminarthrectomy. MIS approaches have been studied clinically in these indications with very satisfying results. As a conclusion, MIS approaches seems to be a relevant and efficient option in the treatment of lumbar degenerative stenosis. LEVEL OF EVIDENCE: IV, retrospective study.

Variation of Global Sagittal Alignment Parameters According to Gender, Pelvic Incidence, and Age.

STUDY DESIGN: Retrospective cross-sectional study. OBJECTIVE: The aim was to describe existing global sagittal alignment parameters across ages and to analyze differences according to gender and pelvic incidence (PI). SUMMARY OF BACKGROUND DATA: Variability with age has been reported. It remains unclear how gender and spinopelvic morphology could additionally influence global alignment parameters. MATERIALS AND METHODS: Radiographs of 2599 individuals (5-93 y) were analyzed. Translation parameters were: Sagittal Vertical Axis (SVA)-C7, SVA-C2, SVA-Center Acoustic Meatus (CAM), C7/Sacrofemoral Distance (SFD) ratio. Inclination parameters were: C7-Vertical Tilt (VT), T1-VT and T9-VT, Odontoid-Hip Axis (OD-HA), OD-CAM. Pelvic compensation parameters were: T1-Pelvic Angle (TPA), Global Tilt (GT), Spino-Sacral Angle (SSA). Global sagittal alignment (GSA) was considered among formulae. The distribution of parameters was analyzed using a Bayesian inference. Correlations with spinopelvic parameters were investigated. RESULTS: SVA-C7, SVA-C2, SVA-CAM were larger in males and high PI, and increased significantly after 50 years (Pr>0.9999). C7/SFD decreased during growth and was larger in low PI (Pr=0.951). There was no correlation with spinopelvic parameters. Age-related variations of inclination parameters were nonsignificant. T1-VT and T9-VT increased with PI and were significantly larger in high PI (Pr>0.95). C7-VT was significantly larger in low PI (Pr>0.9999). OD-HA and OD-CAM were constant and increased after 80 years. TPA and GT increased with PI (Pr>0.9999) and age after 35 years (Pr>0.9999). SSA decreased nonsignificantly after 50 years. TPA correlated with PI (ρ=0.6130) and pelvic tilt (PT) (ρ=0.8375). GT correlated with PI (ρ=0.5961) and PT (ρ=0.8996). SSA correlated with sacral slope (ρ=0.9026). GSA was larger in high PI (Pr>0.9999) and increased after 35 years (Pr>0.9999). GSA correlated with PT (ρ=0.7732). CONCLUSION: Translation parameters increase with age, more prominently in males and high PI. Variations of inclination parameters are smaller. Pelvic compensation parameters and GSA increase with age and are closely related to PT and spinopelvic morphology. LEVEL OF EVIDENCE: Level III.

Clinical predictive model of lumbar curve Cobb angle below selective fusion for thoracic adolescent idiopathic scoliosis: a longitudinal multicenter descriptive study.

PURPOSE: To implement a clinically applicable, predictive model for the lumbar Cobb angle below a selective thoracic fusion in adolescent idiopathic scoliosis. METHODS: A series of 146 adolescents with Lenke 1 or 2 idiopathic scoliosis, surgically treated with posterior selective fusion, and minimum follow-up of 5 years (average 7) was analyzed. The cohort was divided in 2 groups: if lumbar Cobb angle at last follow-up was, respectively, ≥ or < 10°. A logistic regression-based prediction model (PredictMed) was implemented to identify variables associated with the group ≥ 10°. The guidelines of the TRIPOD statement were followed. RESULTS: Mean Cobb angle of thoracic main curve was 56° preoperatively and 25° at last follow-up. Mean lumbar Cobb angle was 33° (20; 59) preoperatively and 11° (0; 35) at last follow-up. 53 patients were in group ≥ 10°. The 2 groups had similar demographics, flexibility of both main and lumbar curves, and magnitude of the preoperative main curve, p > 0.1. From univariate analysis, mean magnitude of preoperative lumbar curves (35° vs. 30°), mean correction of main curve (65% vs. 58%), mean ratio of main curve/distal curve (1.9 vs. 1.6) and distribution of lumbar modifiers were statistically different between groups (p < 0.05). PredictMed identified the following variables significantly associated with the group ≥ 10°: main curve % correction at last follow-up (p = 0.01) and distal curve angle (p = 0.04) with a prediction accuracy of 71%. CONCLUSION: The main modifiable factor influencing uninstrumented lumbar curve was the correction of main curve. The clinical model PredictMed showed an accuracy of 71% in prediction of lumbar Cobb angle ≥ 10° at last follow-up. LEVEL OF EVIDENCE IV: Longitudinal comparative study.

Minimal invasive management of early revision after minimal invasive posterior lumbar fusion.

BACKGROUND: Minimally invasive spine (MIS) fusion is an increasingly common procedure, with advantages over open approach in the form of minimal dissection and superior early clinical outcome. The frequency of complications is known, but the most appropriate surgical revision for this technique remains unclear. HYPOTHESIS: The main hypothesis was that early revision surgery, for acute complications after MIS, was possible through mini-invasive approach. METHODS: A retrospective study of patients undergoing MIS has been performed, with or without transforaminal interbody fusion (TLIF) using specific navigation and ancillary. All surgical revisions were done by minimally invasive approach. Preoperative and surgical data, as well as postoperative complications have been analyzed. The primary endpoint was clinical outcome obtained after surgical revision. RESULTS: Data of 187 patients undergoing MIS procedure at 1-4 levels was analyzed. The rate of early revision (within one month) was 5.3%: 0.5% for infection, 1.6% for compressive hematoma, and 2.1% for misplaced screw. The use of intraoperative navigation decreased the frequency of screw misplacement from 4.5% to 1.4%. The rate of surgical revision was 7.8% for surgeons in their learning curve and 3.6% for experienced surgeons. DISCUSSION: On these large series, MIS early revision rates were lower than previously reported for conventional fusions. Surgeon's experience in MIS procedures seems to be crucial to decrease revision and complications rates. Hemorrhagic complications led to multidisciplinary discussions and the establishment of a management protocol. Surgical revisions can be performed by minimally invasive techniques, regardless of the indication. LEVEL OF EVIDENCE: IV, retrospective study.

Correction of adult spinal deformity with a minimally invasive fusionless bipolar construct: Preliminary results.

INTRODUCTION: Fusion in adult spinal deformity has a high rate of complications. Fusionless constructs in children and percutaneous fixation in adults are now being used routinely. The aim of this study was to evaluate the preliminary results of a minimally invasive fusionless surgical technique used to correct adult spinal deformity. MATERIALS AND METHODS: Thirty-eight patients with an average age of 45 years (15-76) with major spinal deformity requiring extensive arthrodesis from the upper thoracic region to the pelvis were operated consecutively and followed prospectively. Two hooks were implanted at the top and two iliosacral screws at the bottom. Two large rods connected by dominos to two small rods joined the upper hooks to the lower screws. The surgical data (operative time and bleeding), the radiological findings (Cobb angle, sagittal parameters, C7-plumbline AP and lateral), the complication rate and the morbidity were evaluated at the last follow-up visit. RESULTS: The primary curvature was reduced by 40% from a mean of 58.5° (26-146) to 35.2° (3-109) (p<0.001). A clear decrease in operating time (270min) and blood loss (50cc/level) were observed. The length of hospitalization averaged 18 days (6-66), including an 8-15 day long preoperative traction period for 11 patients. We found 7 infectious complications, 11 early mechanical complications and one case of paraplegia due to severe kyphoscoliosis. CONCLUSION: The corrections obtained are comparable to those reported in the literature for standard constructs. Most patients had an uneventful postoperative course. The early complications observed led us to very carefully select the indications. Long-term follow-up is essential.

Posterior-only versus combined anterior/posterior fusion in Scheuermann disease: a large retrospective study.

PURPOSE: The literature shows controversies concerning surgical treatment of Scheuermann's kyphosis between posterior-only fixation and combined anterior/posterior fusion. The aim of this study is to compare the clinical and radiological results and the rate of complications between these two techniques. METHODS: We performed a multicentric retrospective review of 131 patients who underwent primary fusion for Scheuermann's kyphosis divided into two groups: 67 patients operated via posterior approach only and 64 operated via combined anterior/posterior approach. Classical clinical, surgical and radiological data were collected. A descriptive and statistical analysis was performed between the two groups to evaluate the influence of the surgical procedure on the rate of complications, the functional results and radiological correction. RESULTS: The average age was 23 and the average kyphosis was 77 degrees. The mean follow-up was 4.2 years (range 0.1-27.3). There was no difference regarding demographic data, preoperative radiographic data and length of fusion between the two groups. Functional results were good in 81% of cases. Kyphosis correction was on average 15° and the correction of the compensatory lumbar lordosis was 20°. The correction was stable at final follow-up. There was no difference between the two groups in terms of functional results, the complications rate and radiological correction. CONCLUSION: Surgery for Scheuermann's kyphosis gives good and stable functional and radiological results. Given the fact that the two surgical strategies give the same results, it appears that the anterior/posterior fusion technique to treat Scheuermann's kyphosis should be reserved for major deformations. These slides can be retrieved under Electronic Supplementary Material.

Incidence and Risk Factors for Proximal Junctional Kyphosis: Results of a Multicentric Study of Adult Scoliosis.

STUDY DESIGN: This was a retrospective multicentric study. OBJECTIVE: The objective of this study was to determine the different risk factors for development of proximal junctional kyphosis (PJK) in patients with adult scoliosis. SUMMARY OF BACKGROUND DATA: This study was conducted as the reasons for development of PJK in adult scoliosis are still not clear. MATERIALS AND METHODS: In total, 314 patients met the inclusion criteria. The main outcome measure was the PJK, as described by Glattes and colleagues. Extent of the instrumentation, operative time, bleeding, and the use of an osteotomy as well as the type of proximal anchorage were collected. Radiologic variables included preoperative Cobb angles of the lumbar and the thoracic curvatures, pelvic parameters, lumbar lordosis, thoracic kyphosis, and sagittal vertical axis. All measures were performed using the KEOPS software. RESULTS: The mean follow-up of this series was 2.5 years with a female to male ratio of 6.6/1 and a mean age of 56.66 years. The incidence of PJK was 25%. Proximal fixation extended to the proximal thoracic spine (TS) in 39%, to the middle TS in 39.5% of cases, and to the thoracolumbar junction in 20.4%, with a higher incidence of PJK noted in the first group. The proximal anchors had no effect on PJK incidence. Age as well as body mass index had a positive correlation to the incidence of PJK. The association, fusion to sacrum and fusion to the upper TS, is associated with the highest incidence of PJK. Preoperative pelvic tilt had a positive correlation with PJK occurrence. Finally, revision for PJK occurred in 2.3% of all patients and accounted for 15% of revisions. CONCLUSIONS: Increased age, as well as increased body mass index, is a risk factor for the development of PJK. The proximal extent of the construct is also shown to be a risk factor for PJK, but fusion to the sacrum is a risk factor only if fusion extends to the proximal TS. Moderate PJK was observed with undercorrection of the sagittal balance and severe PJKs with overcorrection of the sagittal balance. LEVEL OF EVIDENCE: Level IV.

Limitations and pitfalls of the pedicle screw testing monitoring technique: An in vivo and in vitro study.

OBJECTIVES: Pedicle screw testing is a widely used technique in the field of neuromonitoring for spinal surgery. It was designed by Calancie et al. (1992) in order to detect pedicle breach, one of the major complications of pedicle screw fixation, which can lead to neurological impairment. However, numerous false negative and equivocal results led to its clinical relevance being questioned. We aimed to clarify these discrepancies and characterize electrical parameters underlying this technique. METHODS: In this setting, our study is divided into two parts: (1) a clinical part assessing the difference between direct pedicle hole via the pedicle perforator stimulation and indirect stimulation via the implanted screw; (2) an in vitro study testing the electrical properties (resistivity and conductivity) on a sample of different commonly used pedicle screws. RESULTS: We showed that there were discrepancies between direct perforator stimulation and pedicle screws, especially at high threshold values. These might be attributed to electrical contact discontinuity. In vitro testing revealed that the previously described resistivity variability and the instability of measures are due to the result of slight changes of position of the recording contacts. CONCLUSION: Electrical continuity is crucial in the pedicle screw test technique. This parameter cannot actually be fully ensured and can lead to discrepancies and potentially false negative results. Therefore, we recommend the use of both direct stimulation of the pedicle hole and control testing of the screw. Further studies and improvement of the technique are required to ensure its reliability.

Risk of revision surgery for adult idiopathic scoliosis: a survival analysis of 517 cases over 25 years.

PURPOSE: Little is known about the long-term status of patients operated for spine deformities. The aim of this study was to determine the survival of primary fusion in adult idiopathic scoliosis and identify the risk factors of revision surgery. METHODS: Adult patients who underwent primary fusion for idiopathic scoliosis between 1983 and 2011 were included in a continuous monocentric retrospective series. Any additional surgery was registered for survival analysis. Survival and follow-up were estimated by the Kaplan-Meier method and an analysis was performed to identify the risk factors of revision surgery. RESULTS: This series included 447 women (86.5 %) and 70 men (13.5 %) reviewed after a mean follow-up of 7 years (range 0-26.4). Mean age was 44.4 years. Fusion was performed on a median 11 levels (range 3-15); revision rate was 13 % (CI 10-17), 18 % (CI 14-23) and 20 % (CI 16-26) at 5, 10 and 15 years, respectively. Revision surgery was associated with age, anterior release, length of fusion, the inferior limit of fusion, post-operative sagittal balance and junctional kyphosis. The length of fusion (HR 1.13 per vertebrae fused, p = 0.007) and the lower limit of fusion (HR 5.9, p < 0.001) remained independent predictors of revision surgery on multivariate analysis. CONCLUSION: This series evaluated the risk of revision surgery following spinal fusion for idiopathic scoliosis. Our results show that the risk seemed to increase linearly with a rate of nearly 20 % after 10 years. The length and lower limit of fusion are the main risk factors for revision surgery. Level IV (e.g. case series).

[Scoliosis in adulthood: a constant evolution] / Scolioses à l'âge adulte : une évolution constante

Scoliosis in adulthood : a constant evolution. Scoliosis are increasing after the end of growth. The average rate of worsening is one degree per year for a scoliosis beyond 30°. Well tolered during young adulthood, the scoliosis become symptomatic over 40 years with back pain, radiculalgia, aesthaetic and functionnal discomfort. Severe form could lead to respiratory insufficency. Adolescents and young adults, after surgery, have, most often, a normal life. Neurological complications, severe and exceptional shall be discussed. Over 50 years, the rate of surgical complications increase with long fusion often required and a less robust bone. The knowledge of scoliosis natural evolution and studies about long term surgical results allow the choice between medical treatment and surgery. To establish a prognosis, scoliosis over 20° should be monitored with X-rays, each five years.

Scolioses à l'âge adulte : une évolution constante. Les scolioses évoluent après la fin de la croissance. Le rythme d'aggravation est variable, il est en moyenne de 1° par an pour les scolioses de plus de 30°. Bien tolérées dans la vie d'adulte jeune, les scolioses deviennent après 40 ans symptomatiques, avec des douleurs rachidiennes, des radiculalgies, une gêne esthétique et fonctionnelle. Les formes les plus graves peuvent aboutir à une insuffisance respiratoire. Les adolescents et adultes jeunes opérés mènent une vie le plus souvent normale. Les complications neurologiques graves et exceptionnelles existent et doivent être évoquées. Après 50 ans, les arthrodèses ont un taux de complications qui augmente, avec des montages plus longs dans un os moins solide. La connaissance de l'évolution spontanée des scolioses et des suites à long terme des arthrodèses permet de choisir le mode de traitement médical ou chirurgical. La nécessité d'un consentement le plus éclairé possible est indispensable. Pour établir un pronostic, les scolioses de plus de 20° doivent être surveillées avec des radiographies tous les 5 ans.

[Surgical treatment of lumbar disc herniations]. / Traitement chirurgical de la hernie discale lombaire.

The definitive treatment of lumbar disc herniation with radiculopathy includes interventional spine procedures and surgical treatment (open or micro discectomy). It is indicated in emergency in specific situations: in case of cauda equina syndrome, motor deficit lower or equal to 3/5 or hyperalgic radicular pain resistant to maximal medical therapy, including opioid drugs. In these situations, there is no place for percutaneous treatment techniques; treatment is surgical. Except these emergency situations, a definitive treatment is indicated in case of ineffectiveness of complete medical treatment for at least six weeks. The objective is the treatment of radicular pain; the effect on the associated low back pain is unpredictable. In this context of functional surgery, patient selection is very important. Results of interventional procedures for disc herniation are still poorly documented and should be best carried in the context of evaluation protocols. At present standard treatment remains minimal invasive discectomy.

Traitement chirurgical de la hernie discale lombaire. Le traitement radical de la hernie discale comporte les techniques de traitement percutané et le traitement chirurgical, idéalement à type de microdiscectomie. Il est indiqué en urgence dans des situations bien précises : devant un syndrome de la queue de cheval, un déficit moteur inférieur ou égal à 3/5 d'installation rapide ou une douleur radiculaire hyperalgique résistant au traitement médical maximal, y compris les opiacés. Dans ces contextes d'urgence, il n'y a pas de place aux techniques de traitement percutané, le traitement est chirurgical. En dehors de ces situations d'urgence, le traitement radical est indiqué en cas d'inefficacité d'un traitement médical bien conduit pendant au moins six semaines. L'objectif est le traitement de la douleur radiculaire, l'effet sur la lombalgie associée étant imprévisible. Dans ce contexte de chirurgie fonctionnelle, la sélection des patients est donc très importante. Le recours aux techniques de traitement percutanées est encore mal codifié et doit se faire au mieux dans le cadre de protocoles d'évaluation. Le traitement standard reste à l'heure actuelle la discectomie par voie mini-invasive.

Atypical bilateral pedicle fracture in long-term bisphosphonate therapy.

STUDY DESIGN: A case report with review of the literature. OBJECTIVE: To present a first case of an atraumatic bilateral pedicle fracture of L5 in a patient with long-term risedronate therapy and without any previous history of surgery or fracture. SUMMARY OF BACKGROUND DATA: A few cases of bilateral osteoporotic pedicle fractures have been reported. All were associated with previous or concomitant corporeal compression fractures. Atypical femoral fractures were recently described with long-term bisphosphonate treatment. To our knowledge, there are no previous reports of isolated bilateral pedicle fracture associated with prolonged bisphosphonate therapy. METHODS: A 66-year-old woman treated with risedronate for 10 years and without any history of trauma presented with exacerbation of low back pain. No fracture was noted in her past medical history. RESULTS: A complete workup showed an isolated bilateral recent fracture of the L5 pedicles without evident etiology. Consolidation was achieved after 3 months of bracing. CONCLUSION: We reported the first case of isolated bilateral pedicle fracture in a patient treated with risedronate for 10 years. This may be another atypical fracture in long-term bisphosphonate treatment.

Late paraplegia after scoliosis treatment: an uncommon diagnosis.

We report the case of a young girl treated at age 16 for a progressive scoliosis by posterior instrumented arthrodesis. Ten years later, she suddenly developed lumbar pain and paraplegia. The surgical procedure showed a mass infiltrating the vertebral canal and the dural sheath following a supralaminar hook. Histology revealed a diagnosis of leiomyosarcoma. The outcome was poor with a rapid and fatal extension of the tumor. There is nothing to justify a causal link between the scoliosis and the late onset of a malignant tumor. Nevertheless, we discuss the potential role of diagnostic irradiation consecutive to scoliosis monitoring during growth and the potential role of environmental carcinogens like metallic biomaterials. Finally, rapid intrusion of this extraspinal tumor into the dural sheath resulted in a confusing clinical picture and delayed the diagnosis and treatment of the tumor.