Pulsed Electromagnetic Fields Accelerate Sensorimotor Recovery Following Experimental Disc Herniation.

STUDY DESIGN: An experimental animal study. OBJECTIVE: The aim of this study was to investigate the effect of pulsed electromagnetic fields (PEMF) on recovery of sensorimotor function in a rodent model of disc herniation (DH). SUMMARY OF BACKGROUND DATA: Radiculopathy associated with DH is mediated by proinflammatory cytokines. Although we have demonstrated the anti-inflammatory effects of PEMF on various tissues, we have not investigated the potential therapeutic effect of PEMF on radiculopathy resulting from DH. METHODS: Nineteen rats were divided into three groups: positive control (PC; left L4 nerve ligation) (n = 6), DH alone (DH; exposure of left L4 dorsal root ganglion [DRG] to harvested nucleus pulposus and DRG displacement) (n = 6), and DH + PEMF (n = 7). Rodents from the DH + PEMF group were exposed to PEMF immediately postoperatively and for 3 hours/day until the end of the study. Sensory function was assessed via paw withdrawal thresholds to non-noxious stimuli preoperatively and 1 and 3 days postoperatively, and every 7 days thereafter until 7 weeks after surgery. Motor function was assessed via DigiGait treadmill analysis preoperatively and weekly starting 7 days following surgery until 7 weeks following surgery. RESULTS: All groups demonstrated marked increases in the left hindlimb response threshold postoperatively. However, 1 week following surgery, there was a significant effect of condition on left hindlimb withdrawal thresholds (one-way analysis of variance: F = 3.82, df = 2, P = 0.044) where a more rapid recovery to baseline threshold was evident for DH + PEMF compared to PC and DH alone. All groups demonstrated gait disturbance postoperatively. However, DH + PEMF rodents were able to regain baseline gait speeds before DH and PC rodents. When comparing gait parameters, DH + PEMF showed consistently less impairment postoperatively suggesting that PEMF treatment was associated with less severe gait disturbance. CONCLUSION: These data demonstrate that PEMF accelerates sensorimotor recovery in a rodent model of DH, suggesting that PEMF may be reasonable to evaluate for the clinical management of patients with herniation-associated radiculopathy.Level of Evidence: N/A.

A new parallel closing mechanism for the laminectomy rongeur makes it significantly more precise: a biomechanical and mechanical comparison study.

PURPOSE: To prove that a modified closing mechanism of the rongeur gives better precision compared to the old Kerrison rongeur. METHODS: Forty persons from the departments of orthopaedic surgery, urology and neurosurgery (35 orthopaedic, 2 urology and 3 neurosurgery) took part in the study. All participants were asked to punch ten times in a first step with either the old Kerrison rongeur with the scissors-like handle or the modified punch with a new parallel closing mechanism. In a second step, they punched 10 times with the other instrument. Shaft movement in three dimensions was measured with a stereoscopic, contactless, full-field digital image correlation system. RESULTS: The new rongeur is significantly more precise with less movement in all three dimensions. The mechanical model of the new rongeur shows that the momentum needed to keep the tip at the initial position changes only minimally during the closing act on the new model. CONCLUSION: The new rongeur is more precise compared to the old Kerrison model. It is more robust against changes in the direction of the finger forces and may reduce soreness, fatigue and CTS in spine surgeons. LEVEL OF EVIDENCE: Not applicable: technical study.

Implantation of juvenile human chondrocytes demonstrates no adverse effect on spinal nerve tissue in rats.

PURPOSE: Degenerative disc disease (DDD) is a common disabling condition for millions of individuals. Injection of xenogenic juvenile chondrocytes (XJC) into the disc space has been shown to have a therapeutic potential for disc repair. In the current study, XJC were injected extra-discally on neural structures in an in vivo rat hemilaminectomy model to compare the histological and behavioral effects on XJC and fibrin glue carrier. METHODS: Twenty-four rats were assigned to four groups: cells plus carrier, carrier alone, sham hemi-laminectomy, and a positive control (nerve root ligation). A right-sided hemilaminectomy was performed and the study material was placed on and around the exposed L4 nerve root and the spinal cord. Pre- and postoperatively mechanical allodynia was tested on the ipsilateral hind paw using the von Frey up-down method. The lumbar spines were harvested after 6 and 12 weeks for nerve histology and TNF-α quantification. RESULTS: After a brief period of hyperalgesia, the von Frey data indicate there are no adverse effects of placing XJC on spinal nerve roots in rats. However ligation of nerve root showed significant allodynia compared to the other groups. These behavioral data were supported by histological analyses. CONCLUSIONS: While these results need to be confirmed over a larger period of time, they suggest that XJC transplantation into the disc space shows no adverse effect on nerve tissue.

Prophylactic adjacent-segment vertebroplasty following kyphoplasty for a single osteoporotic vertebral fracture and the risk of adjacent fractures: a retrospective study and clinical experience.

OBJECTIVE This study investigated the benefit of prophylactic vertebroplasty of the adjacent vertebrae in single-segment osteoporotic vertebral body fractures treated with kyphoplasty. METHODS All patients treated with kyphoplasty for osteoporotic single-segment fractures between January 2007 and August 2012 were included in this retrospective study. The patients received either kyphoplasty alone (kyphoplasty group) or kyphoplasty with additional vertebroplasty of the adjacent segment (vertebroplasty group). The segmental kyphosis with the rate of adjacent-segment fractures (ASFs) and remote fractures were studied on plain lateral radiographs preoperatively, postoperatively, at 3 months, and at final follow-up. RESULTS Thirty-seven (82%) of a possible 45 patients were included for the analysis, with a mean follow-up of 16 months (range 3-54 months). The study population included 31 women, and the mean age of the total patient population was 72 years old (range 53-86 years). In 21 patients (57%), the fracture was in the thoracolumbar junction. Eighteen patients were treated with additional vertebroplasty and 19 with kyphoplasty only. The segmental kyphosis increased in both groups at final follow-up. A fracture through the primary treated vertebra (kyphoplasty) was found in 4 (22%) of the vertebroplasty group and in 3 (16%) of the kyphoplasty group (p = 0.6). An ASF was found in 50% (n = 9) of the vertebroplasty group and in 16% (n = 3) of the kyphoplasty group (p = 0.03). Remote fractures occurred in 1 patient in each group (p = 1.0). CONCLUSIONS Prophylactic vertebroplasty of the adjacent vertebra in patients with single-segment osteoporotic fractures as performed in this study did not decrease the rate of adjacent fractures. Based on these retrospective data, the possible benefits of prophylactic vertebroplasty do not compensate for the possible risks of an additional cement augmentation.

Endovascular embolisation is a successful and safe treatment for post-operative arterial complications after total hip arthroplasty and revision surgery.

PURPOSE: Arterial complications are rare but clinically critical during or following total hip arthroplasty (THA) surgery. They usually require secondary interventions, either through open or endovascular approaches. In a retrospective study, we analysed indications for, as well as success and safety of, endovascular embolisation for arterial complications after THA. METHODS: We reviewed all arterial complications that had occurred through THA surgery and been treated by endovascular embolisation. We analysed angiographic findings, endovascular treatment, location in relation to the surgical approach and success of the interventions. RESULTS: Between 1997 and 2013 we performed 3,891 THAs at our hospital. We identified 14 patients with acute arterial complications treated by minimally invasive endovascular embolisation. Clinical findings included swelling of the ipsilateral leg, pain, prolonged wound bleeding, decreased haemoglobin and/or haemodynamic instability. Angiography revealed pseudoaneurysm in 11 patients, arteriovenous fistulas in two and extravasation of contrast media in one. Two patients showed no signs of acute bleeding. Twelve patients were treated, each with a single session of endovascular embolisation; in two additional patients, the haematoma was evacuated. No complications from the endovascular treatment were observed in this series. CONCLUSION: Endovascular embolisation is a safe and successful minimally-invasive method to treat arterial injuries occurring through THA. Therefore, it should be considered as a first-line option of treatment for those injuries.

10-Year Survival of Acetabular Reinforcement Rings/Cages for Complex Hip Arthroplasty.

INTRODUCTION: Acetabular reinforcement rings/ cages (AR) are commonly used for reconstruction of bone defects in complex hip arthroplasty. The aim of this study was to retrospectively investigate the 10-year survival rate of Ganz reinforcement rings and Burch-Schneider cages used in a single institution. MATERIAL AND METHODS: Between September 1999 and June 2002 all ARs, implanted in one institution, were identified. All patients had regular clinical and radiographic follow-up and were included in this study. Their prospectively collected clinical and radiographic data was retrospectively analyzed. In case of death before the 10-year follow-up examination, patient's families or their general practitioner was contacted by telephone. The main outcome measures were survival of the ARs and kind of revision surgery. RESULTS: The 10-year survival rate was 77.7%. At 10-year follow-up, 5/60 (8,3%) patients could not be located and had to be excluded therefore. 27/55 (49,1%) were dead, whereof 22 had no revision of the ARs before death (after a mean of 66 months; range: 0 - 123). Of the remaining 28/55 (50,9%) patients, 23 patients (24 ARs) had no revision of the ARs. CONCLUSION: Despite the high mortality rate of this study's collective, ARs for complex primary or revision total hip arthroplasty provided predictable long term results. LEVEL OF EVIDENCE: Clinical investigation.

The extended medial elbow approach-a cadaveric study.

BACKGROUND: The two most commonly used approaches to expose medial elbow structures are the flexor carpi ulnaris split and the Hotchkiss over-the-top approach. The aim of this study was to define the extended medial approach to the elbow, featuring advantages of over-the-top (proximal exposure) and additional complete exposure of the coronoid and proximal medial ulna, while respecting the internervous plane between the flexor pronator mass and flexor carpi ulnaris muscle. METHODS: In this comparative anatomic study, 12 fresh frozen cadaveric elbows were dissected alternately to study the distal limitation and exposed area of the extended medial elbow approach compared with splitting the flexor carpi ulnaris. RESULTS: Proximal ulna exposure area was comparable between the extended medial elbow approach (average, 840 mm(2)) and the flexor carpi ulnaris split (average, 810 mm(2); P = .44). The extended medial approach was limited distally by the posterior recurrent ulnar artery (mean 68 mm from medial epicondyle), whereas the first motor branch for the flexor carpi ulnaris muscle limited the second approach in 75% of the specimens (mean 29 mm from medial epicondyle, P < .001). CONCLUSIONS: The extended medial elbow approach is a single approach allowing full exposure of the medial elbow and combining the advantages of the over-the-top approach with a safe distal extension to the medial ulna. In contrast to the flexor carpi ulnaris split, our approach respects the internervous plane.

Pre-operative embolisation of spinal metastasis: technique, complication rate and outcome-clinical experience.

PURPOSE: Pre-operative embolisation of metastatic spinal tumours has the potential to decrease intra-operative blood loss. Intra-operative blood loss is multifactorial and one factor may be the embolisation technique used. The purpose of this study was to retrospectively analyse the effect of three different pre-operative embolisation techniques on intra-operative blood loss, complication rate and tumour aetiology in patients treated with a corpectomy and dorsoventral stabilisation at our institution. METHODS: We conducted a retrospective analysis of embolisation procedures for vertebral metastases performed from January 2002 to December 2011. Only pre-operatively embolised patients treated by a single-level hemicorpectomy or corpectomy procedure from T4-L5, including posterior spinal stabilisation using pedicle screws, were included. All patient charts and examinations were analysed regarding the embolisation technique, gender, age, primary tumour, time between the embolisation and surgery, intra-operative blood loss, intra-operative transfusions and complications related to embolisation. RESULTS: We identified a total of 46 patients, 25 male and 21 female patients. The mean age at the time of surgery was 66 years (range 39-84 years). The tumours treated were: 15 (33%) renal cell carcinomas, six (13%) breast carcinomas, five (11%) lung carcinomas, five (11%) urothelial carcinomas, four (9%) myelomas and 11 (24%) miscellaneous types including rectal carcinoma, thymoma and melanoma. Embolisation with coils was performed in 23 patients, particles were used in six and a combination of coils and particles in 18. The mean time between the embolisation and surgery was 23 hours (range 80-4,430 minutes). The median overall intra-operative estimated blood loss (EBL) was 2,300 ml (range 500-15,000 ml). In patients embolised with coils and particles, EBL was 2,200 ml compared to 1,450 ml in patients embolised with particles and 2,500 ml in the coil group. No statistically significant differences between the three groups could be detected. There were no complications related to the embolisation techniques. CONCLUSIONS: Pre-operative embolisation of spinal metastases using coils, particles or a combination of both is a safe and reproducible procedure. In our cohort we reported no complications during the three different embolisation techniques. No statistically significant difference regarding blood loss between the three embolisation techniques could be detected. Our data confirm existing studies concerning the control of intra-operative blood loss using different embolisation techniques. The benefit of embolisation with a combination of coils and particles compared to embolisation with particles only is questionable.

Real-life results of balloon kyphoplasty for vertebral compression fractures from the SWISSspine registry.

BACKGROUND CONTEXT: The Swiss Federal Office of Public Health mandated a nationwide health technology assessment-registry for balloon kyphoplasty (BKP) for decision making on reimbursement of these interventions. The early results of the registry led to a permanent coverage of BKP by basic health insurance. The documentation was continued for further evidence generation. PURPOSE: This analysis reports on the 1 year results of patients after BKP treatment. STUDY DESIGN: Prospective multicenter observational case series. PATIENT SAMPLE: The data on 625 cases with 819 treated vertebrae were documented from March 2005 to May 2012. OUTCOME MEASURES: Surgeon-administered outcome instruments were primary intervention form for BKP and the follow-up form; patient self-reported measures were EuroQol-5D questionnaire, North American Spine Society outcome instrument /Core Outcome Measures Index (including visual analog scale), and a comorbidity questionnaire. Outcome measures were back pain, medication, quality of life (QoL), cement extrusions, and new fractures within the first postoperative year. METHODS: Data were recorded preoperatively and at 3 to 6-month and 1-year follow-ups. Wilcoxon signed-rank test was used for comparison of pre- with postoperative measurements. Multivariate logistic regression was used to identify factors with a significant influence on the outcome. RESULTS: Seventy percent of patients were women with mean age of 71 years (range, 18-91 years); mean age of men was 65 years (range, 15-93 years). Significant and clinically relevant reduction of back pain, improvement of QoL, and reduction of pain killer consumption was seen within the first postoperative year. Preoperative back pain decreased from 69.3 to 29.0 at 3 to 6-month and remained unchanged at 1-year follow-ups. Consequently, QoL improved from 0.23 to 0.71 and 0.75 at the same follow-up intervals. The overall vertebra-based cement extrusion rates with and without extrusions into intervertebral discs were 22.1% and 15.3%, respectively. Symptomatic cement extrusions with radiculopathy were five (0.8%). A new vertebral fracture within a year from the BKP surgery was observed in 18.4% of the patients. CONCLUSIONS: The results of the largest observational study for BKP so far are consistent with published randomized trials and systematic reviews. In this routine health care setting, BKP is safe and effective in reducing pain, improving QoL, and lowering pain_killer consumption and has an acceptable rate of cement extrusions. Postoperative outcome results show clear and significant clinical improvement at early follow-up that remain stable during the first postoperative year.

High Prevalence of Disc Degeneration and Spondylolysis in the Lumbar Spine of Professional Beach Volleyball Players.

BACKGROUND: Beach volleyball is an intensive sport with high impact on the lumbar spine. Low back pain (LBP) is frequent among elite players. Increased prevalence of pathological changes on magnetic resonance imaging (MRI) in the lumbar spine of elite athletes has been reported. HYPOTHESIS: There is an increased prevalence of disc degeneration and spondylolysis in the MRI of the lumbar spine of professional beach volleyball players. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Twenty-nine fully competitive professional male volleyball players (mean age, 28 years) completed outcomes questionnaires and underwent a complete clinical examination and an MRI of their lumbar spine. RESULTS: Whereas 86% of players suffered from LBP during their career, the incidence of LBP in the last 4 weeks was 35%. Pain rated using a visual analog scale (VAS) averaged 3 points (range, 0-8). Twenty-three of 29 players (79%) had at least 1 degenerated disc of Pfirrmann grade ≥3. The most affected spinal levels were L4-5 in 14 (48%) and L5-S1 in 15 players (52%); both levels were involved in 5 players (17%). Six of 29 (21%) players showed a spondylolysis grade 4 according to the Hollenburg classification; there was evidence of spondylolisthesis in 2 players. There was no significant correlation between LBP and MRI abnormalities. CONCLUSION: In the lumbar spine MRI of professional beach volleyball players, the prevalence of disc degeneration is 79%. Spondylolysis (21%) is up to 3 times higher compared with the normal population. Abnormal MRI findings did not correlate with LBP, thus MRIs have to be interpreted with caution.

Cement volume is the most important modifiable predictor for pain relief in BKP: results from SWISSspine, a nationwide registry.

PURPOSE: The effectiveness of vertebral augmentation techniques is a currently highly debated issue. The biomechanical literature suggests that cement filling volumes may play an important role in the "dosage" of vertebral augmentation and its pain alleviating effect. Good clinical data about filling volumes are scarce and most patient series are small. Therefore, we investigated the predictors of pain alleviation after balloon kyphoplasty in the nationwide SWISSspine registry where cement volumes are also recorded. METHODS: All single-level vertebral fractures with no additional fracture stabilization and availability of at least one follow-up within 6 months after surgery were included. The following potential predictors were assessed in a multivariate logistic regression model with the group's average pain alleviation of 41 points on VAS as the desired outcome: patient age, patient sex, diagnosis, preoperative pain, level of fracture, type of fracture, age of fracture, segmental kyphotic deformity, cement volume, vertebral body filling volume, and cement extrusions. RESULTS: There were 194 female and 82 males with an average age of 70.4 and 65.3 years, respectively. Female patients were about twice as likely for achieving the average pain relief compared to males (p = 0.04). The preoperative pain level was the strongest predictor in that the likelihood for achieving an at least 41-point pain relief increased by about 8 % with each additional point of preoperative pain (p < 0.001). A thoraco-lumbar fracture had a three times higher odds for the average pain relief compared with a lumbar fracture (p = 0.03). An A.3.1 fracture only had about a third of the probability for average pain relief compared with an A.1.1 fracture (p = 0.004). Cement volumes up to 4.5 ml only had an approximately 40 % chance for a minimum 41-point pain alleviation as compared with cement volumes of at least 4.5 ml (p = 0.007). In addition, the relationship between cement volume and pain alleviation followed a dose-dependent pattern. CONCLUSIONS: Cement volume was revealed as a significant predictor for pain relief in BKP. Cement volume was the third most important influential covariate and the most important modifiable and operator dependent one. The clear dose-outcome relationship between cement filling volumes and pain relief additionally supports these findings. Cement volumes of >4.5 ml seem to be recommendable for achieving relevant pain alleviation. Patient sex and fracture type and location were further significant predictors and all these covariates should be recorded and reported in future studies about the pain alleviating effectiveness of vertebral augmentation procedures.