Freehand power-assisted pedicle screw placement in scoliotic patients: results on 5522 consecutive pedicle screws

Pedicle screws is the current gold standard in spine surgery, achieving a solid tricolumnar fixation which is unreachable by wires and hooks. The freehand technique is the most widely adopted for pedicle screws placing. While freehand technique has been classically performed with manual tools, there has been a recent trend toward the use of power tools. However, placing a pedicle screw remains a technically demanding procedure with significant risk of complications. The aim of this article is to retrospectively evaluate safety and accuracy of free-hand power-assisted pedicle screw placement in a cohort of patients who underwent correction and fusion surgery for scoliosis (both idiopathic and non-idiopathic) in our department. A retrospective review of all patients with scoliosis who underwent surgery and received a postoperative CT scan in our department in a 9-year period was undertaken. Screw density, number and location of pedicle screws were measured using pre and postoperative full-length standing and lateral supine side-bending radiographs. Then, postoperative CT scan was used to assess the accuracy of screw placement according to Gertzbein-Robbins scale. Malpositioned screws were divided according to their displacement direction. Finally, intra and postoperative neurological complications and the need for revision of misplaced screws were recorded. A total of 205 patients were included, with a follow-up of 64.9 ± 38.67 months. All constructs were high density (average density 1.97 ± 0.04), and the average number of fusion levels was 13.72 ± 1.97. A total of 5522 screws were placed: 5308 (96.12%) were grade A, 141 (2.5%) grade B, 73 (1.32%) grade C. Neither grade D nor grade E trajectories were found. The absolute accuracy (grade A) rate was 96.12% (5308/5522) and the effective accuracy (within the safe zone, grade A + B) was 98.6% (5449/5522). Of the 73 misplaced screws (grade C), 59 were lateral (80.80%), 8 anterior (10.95%) and 6 medial (8.22%); 58 were in convexity, while 15 were in concavity (the difference was not statistically significant, p = 0.33). Intraoperatively, neither neurological nor vascular complications were recorded. Postoperatively, 4 screws needed revision (0.072% of the total): Power-assisted pedicle screw placing may be a safe an accurate technique in the scoliosis surgery, both of idiopathic and non-idiopathic etiology. Further, and higher quality, research is necessary in order to better assess the results of this relatively emerging technique.

High-grade dysplastic spondylolisthesis: surgical technique and case series

PURPOSE

The aim of the present study is to evaluate the results of our all posterior-one stage surgical technique for the reduction and fusion of high-grade high-dysplastic spondylolisthesis.

METHODS

Patients over 11 years old with high-grade spondylolisthesis treated by reduction and circumferential fusion with a posterior-only approach were reviewed. Data about operative time, blood loss, length of stay, intra- and postoperative complications were collected. Meyerding grade (M), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), lumbosacral angle (LSA), slip angle (SLIP), lumbar index (LI) and severity index were measured on preoperative and last follow-up. Sagittal vertical axis (SVA) was used to assess sagittal balance.

RESULTS

Of the 14 included patients, L5-S1 arthrodesis was performed in 12 cases, and L4-S1 was performed in 2 cases. Average surgical time was 275 ± 65 min; average blood loss was 635 ± 375 mL. Average length of stay of was 3.9 ± 1.5 days. The SLIP angle improves from 33.8° ± 7.3° to 6.4° ± 2.5°, (p = 0.002); the lumbosacral angle improves from 68.8° ± 18.6° to 100.7° ± 13.2°, (p = 0.01); and the SVA decreased from 49.4 ± 22.1 mm to 34.4 ± 8.6 mm (p = 0.02). No significant changes were observed in PI, PT and SS. Thoracic kyphosis (TK) and lumbar lordosis (LL) did not change significantly. At last follow-up, no patient had surgical site infection or mechanical complications; no pseudoarthrosis was observed. No revision surgery was performed.

CONCLUSION

Although technically demanding, reduction and fusion with one stage all posterior approach prove to be a safe and effective.

Non-invasive electrical synchrony method to guide para-hisian stimulation implant technique

Introduction

Right ventricular apex stimulation solves electrical disorder but electrical disynchrony can be generated. Left bundle branch block results in heart failure and device upgrade is needed in some cases. Para-hisian stimulation generates a physiological cardiac activation through normal conduction system. Sheaths and special leads are used with current techniques. We developed an implantation technique guided by non-invasive electric synchrony using conventional screw-in leads. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.

Objective

Usefulness and safety of non-invasive cardiac electrical synchrony method using conventional screw-in leads to guide para-hisian device implantation.

Materials and methods

421 patients were evaluated. All patients had indication of ventricular stimulation (pacemaker and ICD). Non-invasive electrical synchrony was performed with Synchromax study during the device implantations in all patients. Synchrony index and curves were analyzed. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous. Attempt numbers, thresholds, fluoroscopy time and dislodgments were analyzed.

Results

Mean age 69 years (±8 years). 67,9% males. 421 devices were implanted (334 pacemakes and 87 ICDs). Sick sinus syndrome was the main pacemaker aetiology and dilated cardiomyopathy was in patients with ICD. Conventional screw-in leads were used in all cases. An implant technique was designed. A J-shaped curve with a small perpendicular curve at the tip is performed in the stylet. On average 1,9 attempts were made. Thresholds average 1,2 mV. High thresholds in 4 patients with selective parahisian stimulation. 7 dislodgments was evidenced (1,6%). Fluoroscopy time average 8,4 min. Type 2 curve and index under 0,4 was obtained in 94,5% of cases.

Conclusions

Para-hisian pacemaker implantation guided by Synchromax method using conventional screw-in leads is safe and useful achieving a physiological stimulation. Few attempts were needed with this new technique. Thresholds were similar to those used in conventional technique.

Funding Acknowledgement

Type of funding source: None

A novel non-invasive electrical synchrony method to improve cardiac resynchronization therapy responders

Introduction

Cardiac resynchronization therapy (CRT) has emerged as an important treatment for patients with heart failure and reduced ejection fraction (EF) despite optimal pharmacological therapy. Some studies showed non-responders rate near 30%. Nowaday there is no gold standard method for selection, evaluation and follow up on this group of patients. Multiple techniques used and operator dependence made echocardiogram failed. Synchromax 2 is a device designed to evaluate non-invasive electrical synchrony. It is fast, reproducible and non-operator dependent. Synchromax was evaluated and correlated with other techniques in previous studies.

Objective

Evaluate CRT response rate guided by electrical synchrony during the device implantation and follow up.

Material and methods

43 patients were evaluated in an institution in Buenos Aires. A ICD-CRT was implanted in all patients due dilated cardiomyopathy, low EF (less than 35%) and left bundle branch block (LBBB). Non-invasive electrical synchrony evaluation (Synchromax 2) was performed in all patients in baseline condition, during device implantation and the follow up. Synchrony index and curves were analyzed. Curve type 4 and index between 0,4 and 0,7 were considered synchronous. Curve type 6 and 10 and index more than 0.7 were considered disynchronous. Interventricular intervals were modified to achieve the best curve and synchrony index. Super responders were considered when EF increased >50%. Baseline and 6 month after implantation echocardiogram were performed.

Results

Mean age 64 years. 39% females. Non-coronary dilated cardiomyopathy was main aetiology (63,1%). EF baseline average was 27%. A baseline index more than 0,7 was in 73,3% of the patients. Curve 6 was the most frequent (55,2%). Follow up average EF was 39% (increased 12%), the super responders rate was 18,6% (8 patients). Type 4 curve and index between 0,4 and 0,7 were achieved in 28 cases (65,1%). EF increased from 23% (baseline) to 42% (follow up). Average 19%. Type 4 curve was not achieved in 15 patients (34,9%). In this group, EF increased from 29% (baseline) to 34% (follow up). Average 5%.

Conclusion

Electrical synchrony evaluation using Synchromax 2 during ICD-CRT device implantation improves responders rate. When synchronous type 4 curve is achieved EF improves significantly. If type 4 curve is not found results will be unsuccessfully. Synchromax is fast, simple and non-operator dependent.

Funding Acknowledgement

Type of funding source: None

Non-selective para-hisian stimulation used for QRS normalization guided by non-invasive electrical synchrony method in patients with electrical conduction disorders

Introduction

Para-hisian stimulation produces a physiological cardiac activation through normal conduction system. Frequently it is used in patients with no electrical conduction disorders. We developed an implant technique guided by non-invasive electrical synchrony using conventional screw-in leads. Non-selective para-hisian stimulation can normalize electrical conduction disorders. Synchromax is a novel device used to evaluate non-invasive cardiac electrical synchrony. It is easy to understand, fast to obtain, non-invasive and reproducible. Synchromax was analyzed in previous studies and correlated with other methods.

Objective

Evaluate usefulness and safety of non-selective para-hisian stimulation guided by non-invasive cardiac electrical synchrony method using conventional screw-in leads to normalize electrical conduction disorders.

Materials and methods

421 patients with para-hisian stimulation were analyzed retrospectively. 139 patients had different intraventricular and auriculo-ventricular electrical disorders. Non-selective para-hisian stimulation guided by no-invasive electrical synchrony method (Synchromax) was performed in all cases. Synchrony index and curves were analyzed according curves chart. Type 2 curve and index between 0,1 and 0,4 were considered synchronous. Type 8 curve and index more than 0.7 were considered dyssynchronous.

Results

Mean age 71 years (±7 years). 65,4% males. 30,9% had 2° and 3° grade AV block associated. Patients were divided in 5 groups:

1-Right bundle branch block (RBBB): 43 patients

2-Left bundle branch block (LBBB): 33 patients

3-Brugada Syndrome: 8 patients

4-Left anterior hemi-block (LAHB) 30 patients.

5-RBBB associated with LAHB: 25 patients.

QRS normalization was achieved in 87% of the cases using non-selective para-hisian stimulation guided by Synchromax with conventional screw in leads. A ventricular approach was performed during implantation. Electrical synchrony was not solved in 13% of patients mostly in LBBB and RBBB associated with LAHB. Two dislodgments were evidenced.

Conclusions

Non-selective para-hisian stimulation guided by Synchromax method using conventional screw in leads solved most of intraventricular electrical disorders. It is also safe to use in patients with auriculo-ventricular electrical disorder.

Funding Acknowledgement

Type of funding source: None

Estimation of sex from the hyoid body in skeletal individuals from archeological sites

Recent forensic studies have shown that the hyoid bone is a sexually dimorphic element of the human skeleton. Given the advanced techniques of collecting human remains in archeological and forensic contexts, the recovery of hyoid bones is now more frequent in skeletal samples. For that reason the authors propose a new method for estimating sex based on hyoid bodies from archeological sites. The study has been conducted on well-preserved hyoids of skeletal remains of 64 adult individuals (44 males and 20 females) dated from the pre-Roman to the medieval periods. The authors considered 10 linear measurements of the hyoid body. The most significant measurements showing sexual dimorphism are the body height, body length, and the maximum and minimum diameter of the articular facet for the greater horn. Discriminant function analysis achieved the allocation accuracy between 75.0% and 88.0%, depending on the measurement collected. This method represents a new, useful and easy way for increasing biological information when assessing the sex of adult human remains from an archeological sample.

[Breast scintigraphy with 99mTc-MIBI in the study of breast cancer]

BACKGROUND

The literature latest data point out the 99mTc-MIBI scintimammography role as a mammography diagnostic complement for a better nosologic definition of the breast nodular pathology. The object of this study is to evaluate the device sensibility and specificity with reference to the several dimensions of the neoplastic nodule.

METHODS

A group of 50 patients, with breast nodule has been studied comparing scintimammography, mammography, echography and istological examination of the removed nodule.

RESULTS

38 nodules out of 50 were carcinomas, 22 were T1 and 16 T2. As far as scintimammography is concerned, the sensibility is 86% in T1 grade and 100% in T2 grade. The specificity is 91.6%.

CONCLUSIONS

Since the mammography often need integration with invasive examinations, (aspiration biopsy, and biopsy) scintigraphy-mammography, global specificity 92%, is suggested as a second level examination in the mammary nodule diagnosis, for the simple performance and for the little risk for the patient.

[Deep venous thrombosis in pregnancy: diagnostic difficulties and therapeutic indications. Discussion of a clinical case]

Pregnancy is a risk factor for deep and superficial venous thrombosis because of hemodynamic changes and modifications of the coagulation and fibrinolitic systems. In case of a patient suffering from a congenital or acquired thrombophilia, risk of severe and recurrent thrombosis becomes much higher, with the possibility of a life threatening complication as pulmonary embolism. Recently a number of congenital thombophilic syndromes have been described, in particular congenital hereditary deficit of coagulation inhibitors. Among the acquired pathologies, the antiphospholipid syndrome has been recently object of studies. Diagnostic and therapeutic options are still controversial. The authors present a case of recurrent deep vein thrombosis in pregnancy treated with positioning of a caval filter for the prophylaxis of pulmonary embolism. Diagnostic difficulties are discussed, as the patient presented with low levels of the coagulation inhibitor protein S, and also circulating antibodies anticardiolipin.

[Gn-RH analogs in the treatment of benign gynecologic diseases: current trends]

Gn-RH analogues have been recently employed for the treatment of oestrogen-dependent benign gynaecological disorders, such as uterine myomata, endometriosis or metrorrhagia. They induce a "pharmacological castration", inducing a marked reduction of serum oestrogen levels. They proved more effective than other drugs used up to now in the medical treatment of these benign gynaecological diseases. Thus they were initially employed in every case. Later it became clear that Gn-RH analogues need a selective indication. The authors herein report their series of 70 patients with benign gynaecological disorders (45 uterine fibroids, 10 endometriosis, 15 metrorrhagia), treated with a Gn-RH analogue depot for 2-3 months preoperatively. They evaluated the efficacy of the treatment in the group with uterine fibroids in terms of disappearance of metrorrhagia, better haemoglobin level in anaemic patients, reduction of fibroids size allowing for a simpler and less extensive surgery (vaginal surgery, myomectomy, hysteroscopic resection). The authors discuss those cases when preoperative treatment with Gn-RH analogues is not indicated, or should be employed only under careful surveillance (in the preparation of multiple myomectomies, big submucosal myomas). In the group of 10 patients with endometriosis we observed the disappearance of pelvic pain and dyspareunia, whereas the size of endometriomas was only minimally reduced. The authors discuss the usefulness of this treatment in case of patients with endometriosis grade I or II (minimal or mild), with desire of children. In the group of 15 perimenopausal patients with metrorrhagia, 10 became amenorrhoic after termination of treatment, thus avoiding surgery. The major benefit for the other 5 patients was a better haemoglobin level at the time of surgery.

Reduced virulence in ciprofloxacin-resistant variants of Pseudomonas aeruginosa strains

Pseudomonas aeruginosa strains resistant to ciprofloxacin were obtained from parental strains by serial transfer through subinhibitory concentrations of the drug. They showed reduced virulence for mice, and also increased sensitivity to aminoglycosides.

[Electrocardiographic changes in acute abdomen]

We have examined the electrocardiograms of 516 patients hospitalized for acute abdomen. We have excluded from this research the younger patients than 14 years, those with shock, those with clinical signs of cardiopathy, those with electrolytic alterations and those executing anti-arythmic or anti-depressing therapy. We have found changes of repolarization and of rhythm. The changes of regularization consisted in flottening-inversion of T wave in the precordial and/or limb leads associated sometimes at negative deflection of the ST tract in the same leads. The changes of rhythm consisted in atrial or ventricular extrasystoles, paroxismal atrial tachycardia, paroxysmal atrial fibrillation. Sometimes the changes of repolarization and rhythm were associated. We have discussed the possible pathogenetic mechanisms answerable for these changes; sympathetic adrenergic activation mediate or no from a parasympathetic reflex, reduction of intra-cellular potassium, activation of enzymatic systems, reabsorption of toxic substaces. The Authors have underlined the benignity of these ECG changes, disappearing after resolution of abdominal disease, and the necessity of a correct interpretation of those, to avoid the arising of a iatrogenic disease.

[Metastatic syndrome involving multiple cranial nerves on the right]

Reported is a patient who has shown, over a period of five months, a progressive involvement of the V, VI, VII; IX, X, XI, cranial nerves of the right side. Radiologically, an osteolithic lesion of the right petrous pyramid, attributed to a metastasis of prostatic carcinoma, has been demonstrated. The main syndromes of the base of the skull involving the pertinent cranial nerves are revised, and it is concluded that the patient realizes a combination of the syndromes of Gradenigo and Vernet.