Study design Systematic review. Objective To review the published literature on the use of pedicle screws in pediatric spinal deformity to quantify the risks and complications associated with pedicle screw instrumentation, particularly in the thoracic spine. Summary of background data The use of pedicle screws in adolescent scoliosis surgery is common. Although many reports have been published regarding the use of pedicle screws in pediatric patients, there has been no systematic review on the risks of complications. Methods PubMed, Ovid Medline, and Cochrane databases were searched for studies reporting the use of thoracic pedicle screws in pediatric deformity. We excluded articles dealing with neuromuscular scoliosis or bone dysplasia to focus mostly on adolescent thoracic idiopathic scoliosis and the likes. We then searched for cases reports dealing with thoracic pedicle screws complications. Results This systematic review retrieved 21 studies with a total of 4570 pedicle screws in 1666 patients. The mean age of the patients was 17.6 years; 812 patients were women and 252 were men, and 5 studies did not identify sex. Overall, 518 (4.2%) screws were reported as malpositioned. However, in studies in which postoperative computed tomography scans were done systematically, the rate of screw malpositioning was as high as 15.7%. The reported percentage of patients with screw malpositioned is around 11%. Eleven patients underwent revision surgery for instrumentation malposition. Other complications reported include loss of curve correction, intraoperative pedicle fracture or loosening, dural laceration, deep infection, pseudarthrosis, and transient neurologic injury. There were no major vascular complications reported in these 21 studies. We could identify 9 case report articles dealing with complications of pedicle screws. Such complications were mostly either vascular (10 cases) or neurologic (4 cases), without any irreversible complications. Conclusion Malposition is the most commonly reported complication of thoracic pedicle screw placement, at a rate of 15.7% per screw inserted with postoperative computed tomography scans. The use of pedicle screws in the thoracic spine for the treatment of pediatric deformity has been reported to be safe despite the high rate of patients with malpositioned screws (11%). Major complications, such as neurologic or vascular injury, were almost never reported in this literature review of case series. Cases reports on the other hand have started to identify such complications.

Complications of pedicle screw fixation in scoliosis surgery: a systematic review.

STUDY DESIGN Retrospective review of a multicenter database. OBJECTIVE To determine the complication rates associated with surgical treatment of pediatric scoliosis and to assess variables associated with increased complication rates. SUMMARY OF BACKGROUND DATA Wide variability is reported for complications associated with the operative treatment of pediatric scoliosis. Limited number of patients, surgeons, and diagnoses occur in most reports. The Scoliosis Research Society Morbidity and Mortality (M&M) database aggregates deidentified data, permitting determination of complication rates from large numbers of patients and surgeons. METHODS Cases of pediatric scoliosis (age ≤18 years), entered into the Scoliosis Research Society M&M database between 2004 and 2007, were analyzed. Age, scoliosis type, type of instrumentation used, and complications were assessed. RESULTS A total of 19,360 cases fulfilled inclusion criteria. Of these, complications occurred in 1971 (10.2%) cases. Overall complication rates differed significantly among idiopathic, congenital, and neuromuscular cases (P < 0.001). Neuromuscular scoliosis had the highest rate of complications (17.9%), followed by congenital scoliosis (10.6%) and idiopathic scoliosis (6.3%). Rates of neurologic deficit also differed significantly based on the etiology of scoliosis (P < 0.001), with the highest rate among congenital cases (2.0%), followed by neuromuscular types (1.1%) and idiopathic scoliosis (0.8%). Neur-omuscular scoliosis and congenital scoliosis had the highest rates of mortality (0.3% each), followed by idiopathic scoliosis (0.02%). Higher rates of new neurologic deficits were associated with revision procedures (P < 0.001) and with the use of corrective osteotomies (P < 0.001). The rates of new neurologic deficit were significantly higher for procedures using anterior screw-only constructs (2.0%) or wire-only constructs (1.7%), compared with pedicle screw-only constructs (0.7%) (P < 0.001). CONCLUSION In this review of a large multicenter database of surgically treated pediatric scoliosis, neuromuscular scoliosis had the highest morbidity, but relatively high complication rates occurred in all groups. These data may be useful for preoperative counseling and surgical decision-making in the treatment of pediatric scoliosis.

Complications in the surgical treatment of 19,360 cases of pediatric scoliosis: a review of the Scoliosis Research Society Morbidity and Mortality database.

Object. In this, the first of two articles regarding C1–2 transarticular screw fixation, the authors assessed the rate of fusion, surgery-related complications, and lessons learned after C1–2 transarticular screw fixation in an adult patient series. Methods. The authors retrospectively reviewed 191 consecutive patients (107 women and 84 men; mean age 49.7 years, range 17–90 years) in whom at least one C1–2 transarticular screw was placed. Overall 353 transarticular screws were placed for trauma (85 patients), rheumatoid arthritis (63 patients), congenital anomaly (26 patients), os odontoideum (four patients), neoplasm (eight patients), and chronic cervical instability (five patients). Among these, 67 transarticular screws were placed in 36 patients as part of an occipitocervical construct. Seventeen patients had undergone 24 posterior C1–2 fusion attempts prior to referral. The mean follow-up period was 15.2 months (range 0.1–106.3 months). Fusion was achieved in 98% of cases followed to commencement of f...

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Atlantoaxial transarticular screw fixation: a review of surgical indications, fusion rate, complications, and lessons learned in 191 adult patients.

https://www.oarsijournal.com/article/S1063-4584(15)01333-3/pdf

Aging and age related stresses: a senescence mechanism of intervertebral disc degeneration.

Literature studies showed a very wide range of pedicle screw loosening rates after thoracolumbar stabilization, ranging from less than 1 to 15 % in non-osteoporotic patients treated with rigid systems and even higher in osteoporotic subjects or patients treated with dynamic systems. Firstly, this paper aims to investigate how much this complication is affecting the success rate of pedicle screw fixation, in both non-osteoporotic and osteoporotic patients, and to discuss the biomechanical reasons which may be related to the variability of the rates found in the literature. The secondary aim was to summarize and discuss the published definitions and conventions about screw loosening from a clinical and radiological point of view. Narrative literature review. Screw loosening appears to be a minor problem for fixation and fusion of healthy, non-osteoporotic bone. Pedicle screw fixation in osteoporotic bone is believed to be at risk of loosening, but clinical data are actually scarce. Both expandable and augmented screws may be a viable option to reduce the risk of loosening, but clinical evidence is missing. Posterior motion-preserving implants seems to have a significant risk of screw loosening. Standardization appears to be lacking regarding the radiological assessment. Marked differences in the loosening rates found based either on planar radiography or on CT scanning were observed. Reported loosening rates primarily depended on the protocol used for the clinical examination during follow-up and on the conventions used for the radiological assessment. Aiming to a better comparability of published data, we recommend the authors of clinical studies to describe which criteria were used to assess a loosened screw, as well as the protocol of the clinical follow-up examination. Low-dose CT should be used for the assessment of screw loosening whenever possible.

Pedicle screw loosening: a clinically relevant complication?

Study design A retrospective study. Objective To analyze complications with thoracic pedicle screws in scoliosis treatment at our Department over a 3-year period (1999-2001). Summary of background data The use of pedicle screws remains controversial for thoracic scoliosis for fear of complications. Methods A total of 115 consecutive patients who underwent posterior fusion using 1035 transpedicular thoracic screws were reviewed. All patients presented a main thoracic scoliosis with a mean Cobb angle of 75.4 degrees (range, 60 degrees -105 degrees ). For thoracic screw placement, a mini-laminotomy technique was used, inserting a spatula inside the vertebral canal to palpate the borders of the pedicle. Postoperative CT scan was used in 25 patients (21.7%) to study a total of 311 screws, when the screw position was questionable. Results An independent spine surgeon retrospectively reviewed medical records and radiographs of the patients, at a mean follow-up of 4 years. There were 18 screws misplaced (1.7%) in a total of 13 patients (11.3%). Screw malposition was symptomatic only in 1 patient (pleural effusion and fever) and asymptomatic in the other 12 cases (10.4%). Other complications included intraoperative pedicle fractures in 15 patients (13%), dural tears (without neurologic complications) in 14 cases (12.1%), and superficial wound infections in 2 (1.7%). Another operation for screw removal was performed in 5 patients (4.3%), due to pleural effusion (in 1 case), asymptomatic late lateral loosening of a malpositioned screw (in 1), and the possible future risks related the intrathoracic screw position despite the lack of any symptoms (in 3). Two cases (1.7%) were retreated due to wound infection, without removing instrumentation. There was no loss of correction at follow-up. Conclusions The thoracic pedicle screw placement in scoliosis patients requires utmost caution. The mini-laminotomy technique was beneficial in increasing safety of the procedure with an acceptable incidence of complications.

Complications of thoracic pedicle screws in scoliosis treatment.

The treatment of thoracic adolescent idiopathic scoliosis (AIS) of more than 80° traditionally consisted of a combined procedure, an anterior release performed through an open thoracotomy followed by a posterior fusion. Recently, some studies have reassessed the role of posterior fusion only as treatment for severe thoracic AIS; the correction rate of the thoracic curves was comparable to most series of combined anterior and posterior surgery, with shorter surgery time and without the negative effect on pulmonary function of anterior transthoracic exposure. Compared with other studies published so far on the use of posterior fusion alone for severe thoracic AIS, the present study examines a larger group of patients (52 cases) reviewed at a longer follow-up (average 6.7 years, range 4.5–8.5 years). The aim of the study was to evaluate the clinical and radiographic outcome of surgical treatment for severe thoracic (>80°) AIS treated with posterior spinal fusion alone, and compare comprehensively the results of posterior fusion with a hybrid construct (proximal hooks and distal pedicle screws) versus a pedicle screw instrumentation. All patients (n = 52) with main thoracic AIS curves greater than 80° (Lenke type 1, 2, 3, and 4), surgically treated between 1996 and 2000 at one institution, by posterior spinal fusion either with hybrid instrumentation (PSF–H group; n = 27 patients), or with pedicle screw-only construct (PSF–S group; n = 25 patients) were reviewed. There were no differences between the two groups in terms of age, Risser’s sign, Cobb preoperative main thoracic (MT) curve magnitude (PSF–H: 92° vs. PSF–S: 88°), or flexibility on bending films (PSF–H: 27% vs. PSF–S: 25%). Statistical analysis was performed using the t test (paired and unpaired), Wilcoxon test for non-parametric paired analysis, and the Mann–Whitney test for non-parametric unpaired analysis. At the last follow-up, the PSF–S group, when compared to the PSF–H group had a final MT correction rate of 52.4 versus 44.52% (P = 0.001), with a loss of −1.9° versus −11.3° (P = 0.0005), a TL/L correction of 50 versus 43% (ns), a greater correction of the lowest instrumented vertebra translation (−1.00 vs. −0.54 cm; P = 0.04), and tilt (−19° vs. −10°; P = 0.005) on the coronal plane. There were no statistically significant differences in sagittal and global coronal alignment between the two groups (C7-S1 offset: PSF–H = 0.5 cm vs. PSF–S = 0 cm). In the hybrid series (27 patients) surgery-related complications necessitated three revision surgeries, whereas in the screw group (25 patients) one revision surgery was performed. No neurological complications or deep wound infection occurred in this series. In conclusion, posterior spinal fusion for severe thoracic AIS with pedicle screws only, when compared to hybrid construct, allowed a greater coronal correction of both main thoracic and secondary lumbar curves, less loss of the postoperative correction achieved, and fewer revision surgeries. Posterior-only fusion with pedicle screws enabled a good and stable correction of severe scoliosis. However, severe curves may be amenable to hybrid instrumentation that produced analogous results to the screws-only constructs concerning patient satisfaction; at the latest follow-up, SRS-30 and SF-36 scores did not show any statistical differences between the two groups.

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Posterior fusion only for thoracic adolescent idiopathic scoliosis of more than 80°: pedicle screws versus hybrid instrumentation

This study is a retrospective case series review of patients with adolescent idiopathic scoliosis (AIS) who were revised more than 1 year after the index procedure, due to a late-developing deep wound infection, to determine onset, bacteriology, possible influence of implant alloy (titanium vs. stainless-steel) and treatment outcome of patients. From a total of 540 patients who underwent posterior-only fusion for AIS from 1993 through 2005 at our institution, 15 cases (2.77%) were revised due to a late-developing post-operative infection: there were six males and nine females, with an average age at initial surgery of 15.8 years (range 12-18). Late infections occurred at a mean of 70 months (15-95) after the index procedure. The implant alloy used was a stainless-steel instrumentation in 11 patients (4.56% of 241) and a titanium one in 4 patients (1.33% of 299): there was an higher incidence of late infections in stainless-steel alloy group of patients (P < 0.0001). Complete removal of instrumentation was performed in nine patients, obtaining in all cases wound healing and no symptoms of infection, at a minimum 3 years follow-up. In the other six patients, presenting less severe clinical signs of infections, an attempt to save/replace the previous instrumentation was performed, but a complete instrumentation removal had to be performed 11.6 months later (range 3-24) for the persistence or recurrence of infection: all patients healed uneventfully at a minimum 3 years follow-up. Intraoperative cultures were obtained in all 15 cases, being positive in 13 cases (S. epidermidis in 5 patients, S. aureus in 3, Propionibacterium acnes in 1, Serratia marcescens in 1, Propionibacterium acnes + S. epidermidis in 1, S. aureus + S. epidermidis in 1 and coagulase-negative Staphylococci in 1). None presented at latest follow-up scoliosis progression: there was no statistically significant difference between final and pre-operative revision surgery values (P = 0.17). In conclusion, treatment of late-developing post-operative infection in AIS surgery required complete removal of the implant, continuous drain and adequate antibiotic therapy based on intraoperative swab antibiogram. Titanium alloy instrumentations resulted less subject to late post-operative infections, when compared to stainless-steel ones (P < 0.0001).

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Late-developing infection following posterior fusion for adolescent idiopathic scoliosis

Study design A retrospective study. Objective To analyze outcomes after dynamic stabilization without fusion in degenerative lumbar scoliosis in elderly patients. Summary of background data Frequent complications of posterolateral instrumented fusion have been reported after treatment of degenerative lumbar scoliosis in elderly patients. The use of dynamic stabilization without fusion can be advocated to reduce such adverse effects, being less invasive, with shorter operation time and less blood loss. No study in the literature has analyzed outcomes of dynamic stabilization without fusion in these degenerative deformities. Methods Twenty-nine elderly patients (average age, 68.5 years; range, 61-78) with degenerative lumbar scoliosis, undergoing dynamic stabilization (Dynesys system) without fusion combined with decompressive laminectomy, in cases with associated stenosis, were analyzed. Stenosis of the vertebral canal was associated in 27 patients (93.1%); 13 cases (44.8%) also presented a degenerative spondylolisthesis. An independent spine surgeon retrospectively reviewed all the patients' medical records and radiographs to assess operative data and surgery-related complications. Preoperative, postoperative, and follow-up questionnaires were obtained to evaluate clinical outcomes. Results The mean follow-up time was 54 months (range, 39-68). Oswestry Disability Index, Roland Morris Disability Questionnaire, and back pain and leg pain visual analogue scale scores received a statistically significant improvement at last control; the mean improvement was 51.6% for Oswestry Disability Index (P = 0.01), 58.2% for Roland Morris Disability Questionnaire (P = 0.01), 51.7% for leg pain (P = 0.02), and 57.8% for back pain (P = 0.01). Radiographically, degenerative scoliosis and associated spondylolisthesis resulted stable at follow-up with a moderate correction: the average scoliosis Cobb angle was 16.9 degrees (range, 12 degrees -37 degrees) before surgery and 11.1 degrees (range, 4 degrees -26 degrees) at last follow-up, with a 37.5% mean correction (P = 0.01); the anterior vertebral translation was 18.9% (range, 12%-27%) before surgery and 17% (range, 0%-27%) at follow-up, for a 14.6% mean correction (range, 0%-100%) (P = 0.02). No implant-related complications (screw loosening or breakage) or loss of correction were observed. Four cases (13.8%) presented an asymptomatic radiolucent line around screws of the S1 level without screw loosening. Six patients (20.7%) showed minor complications (ileus in 2 cases, urinary tract infection in 2, transient postoperative delirium in one, and respiratory difficulties after surgery in another patient). In 2 other patients (6.8%) incurred major complications, both requiring a revision surgery, for a misplaced screw on L5 and junctional disc degeneration at the lower level respectively. No neurologic complications occurred. Conclusion Dynamic stabilization with pedicle screws in addition to decompressive laminectomy resulted a safe procedure in elderly patients with degenerative lumbar scoliosis; it was able to maintain enough stability to prevent progression of scoliosis and instability, enabling a wide laminectomy in cases of associated lumbar stenosis. This nonfusion stabilization technique was less aggressive than instrumented fusion and obtained a statistically significant improvement of the clinical outcome at last follow-up.

Dynamic stabilization for degenerative lumbar scoliosis in elderly patients

Background Interbody fusion represents an efficient surgical treatment in degenerative lumbar disease, achieving satisfying outcome in >90% of cases. Various studies have affirmed the advantages of percutaneous and minimally invasive techniques with regard to minimized damage on soft tissues during surgical procedure, but their efficacy in comparison with the classic open surgical procedures has not yet been demonstrated. Materials and methods This is a retrospective study. We compared 30 consecutive patients affected by disk degenerative disease or grade I degenerative spondylolisthesis that were treated with minimally invasive transforaminal lumbar interbody fusion (mini-TLIF) to a group of 34 consecutive patients presenting similar pathologic findings and demographic characteristics that underwent interbody fusion by traditional open approach (open-TLIF). All patients were treated between 2006 and 2010. Patients' mean age was 46 years (min 28-max 56) and 51 years (min 32-max 58), respectively. Mean follow-up was 23 months (min 12-max 38) and 25 months (min 12-max 40), respectively. Clinical evaluation was performed by using Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) questionnaires. Radiographic evaluation was performed on standing and dynamic x-rays before operation and at final follow-up. Results There was a statistically significant improvement in clinical scores (VAS and ODI) in both groups. Early postoperative VAS score was significantly lower in the mini-TLIF group. Mean hospital stay and mean blood loss were significantly higher in the open-TLIF group than in the mini-TLIF group (7.4 vs. 4.1 d and 620 vs. 230 mL, respectively). Surgical time length of the procedure was higher in the mini-TLIF group. There were no major neurological complications in any of the patients. At final follow-up, radiographic evaluation showed good implant stability in both groups. Conclusions Mini-TLIF is a safe and efficient procedure and, when correctly and carefully performed, can reach good results, similar to those obtained with traditional open surgical techniques, even though it may require a longer surgical time at least during the first stages of the learning curve. Reduced surgical invasiveness, short hospital stay, and limited blood loss represent the major advantages of minimally invasive technique.

Mario Di Silvestre

Papers

Complications of thoracic pedicle screws in scoliosis treatment.

Posterior fusion only for thoracic adolescent idiopathic scoliosis of more than 80°: pedicle screws versus hybrid instrumentation

Late-developing infection following posterior fusion for adolescent idiopathic scoliosis

Dynamic stabilization for degenerative lumbar scoliosis in elderly patients

Transforaminal Lumbar Interbody Fusion in Degenerative Disk Disease and Spondylolisthesis Grade I: Minimally Invasive Versus Open Surgery.