The use of ultrasound in comparison to radiography in magnetically controlled growth rod lengthening measurement: a prospective study

Yoon, Wai Weng; Chang, Angela; Tyler, Philippa; Butt, Sajid; Raniga, Sameer; Noordeen, Hilali

doi:10.1007/s00586-014-3589-z

Cited by 27 publications

(17 citation statements)

References 11 publications

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“…Our study indicates that only 8% of the ERC readings were accurate, while 74% of the ERC reading overestimated the actual rod lengthening. Previous studies have focused on assessing the reliability of using ultrasound rather than radiographs for assessing distraction in MCGR [4,5]. A recent study has shown somewhat similar findings to ours [6].…”

Section: Discussionsupporting

confidence: 82%

“…There is an increasing trend towards the use of ultrasound as a method of assessing the amount of lengthening because there is no risk of radiation exposure. Ultrasound has previously been validated by two studies as a reliable method of measuring distractions with gold standard radiographs as controls [4,5]. In our centre, distractions are carried out at 8-10 weekly intervals.…”

Section: Introductionmentioning

confidence: 99%

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Does the external remote controller’s reading correspond to the actual lengthening in magnetic-controlled growing rods?

et al. 2020

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Purpose Magnetic-controlled growing rods (MCGRs) are now routinely used in many centres to treat early-onset scoliosis (EOS). MCGR lengthening is done non-invasively by the external remote controller (ERC). Our experience suggests that there may be a discrepancy between the reported rod lengthening on the ERC and the actual rod lengthening. The aim of this study was to investigate this discrepancy. Methods This was a prospective series. Eleven patients who were already undergoing treatment for EOS using MCGRs were included in this study. Results One hundred and ninety-two sets of ultrasound readings were obtained (96 episodes of rod lengthening on dual-rod constructs) and compared to their ERC readings. Only 15/192 (7.8%) readings were accurate; 27 readings (14.9%) were false positive; and 8 readings (4.2%) were an underestimation while 142 readings (74.0%) were an overestimation by the ERC. Average over-reporting by the ERC was 5.31 times of the actual/ultrasound reading. When comparing interval radiographs with lengthening obtained on ultrasound, there was a discrepancy with an average overestimation of 1.35 times with ultrasound in our series. There was a significant difference between ERC and USS (p = 0.01) and ERC and XR (p = 0.001). However, there was no significant difference between USS and XR (p > 0.99). Conclusion The reading on the ERC does not equate to the actual rod lengthening. The authors would recommend that clinicians using the MCGR for the treatment of early-onset scoliosis include pre-and post-extension imaging (radiographs or ultrasound) to confirm extension lengths at each outpatient extension. In centres with ultrasound facilities, we would suggest that patients should have ultrasound to monitor each lengthening after distraction but also 6-month radiographs.

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Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Does the external remote controller’s reading correspond to the actual lengthening in magnetic-controlled growing rods?

et al. 2020

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“…A recent clinical study suggests that patients previously treated with the traditional growing rods can be converted to MCGRs with comparable positive results [12]. Clinical cases reporting pin fracture and failure to distract have been published over the last 2 years [11][12][13][14][15]; this is the first retrieval paper using state-of-the-art forensic analysis to determine the mechanism leading to pin fracture. We examined nine retrieved MCGRs and found that a third of them had a fractured pin.…”

Section: Discussionmentioning

confidence: 99%

“…The lengthening procedure lasts approximately 40 s per rod and the total length is measured using a plain radiograph [8]. Recent studies have also investigated the reliability of other imaging modalities, including ultrasound [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Analysing a mechanism of failure in retrieved magnetically controlled spinal rods

et al. 2017

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Purpose We aim to describe a mechanism of failure in magnetically controlled growth rods which are used for the correction of the early onset scoliosis. Methods This retrieval study involved nine magnetically controlled growth rods, of a single design, revised from five patients for metal staining, progression of scoliosis, swelling, fractured actuator pin, and final fusion. All the retrieved rods were radiographed and assessed macroscopically and microscopically for material loss. Two implants were further analysed using micro-CT scanning and then sectioned to allow examination of the internal mechanism. No funding was obtained to analyse these implants. There were no potential conflicts interests. Results Plain radiographs revealed that three out of nine retrieved rods had a fractured pin. All had evidence of surface degradation on the extendable telescopic rod. There was considerable corrosion along the internal mechanism. Conclusions We found that a third of the retrieved magnetically controlled growth rods had failed due to pin fracture secondary to corrosion of the internal mechanism. We recommend that surgeons consider that any inability of magnetically controlled growth rods to distract may be due to corrosive debris building up inside the mechanism, thereby preventing normal function.

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“…However, loosening of anchor points, ploughing of screws or rod fractures can only be detected on radiographs. Recently published results showing equivalent measurements with ultrasound and radiographs [27,28]. In our institution we have gained ample experience with ultrasound but have not established it as a routine to substitute radiography.…”

Section: Discussionmentioning

confidence: 94%

A Minimum of Two Years Results of Magnetically Controlled Growing Rods for Early Onset Scoliosis

Burstein¹,

Rupprecht²,

Kunkel³

et al. 2017

J Spine

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Objectives: To determine mid-term results and complications of a single center on magnetically controlled growing rod (MCGR) technique in Early Onset Scoliosis (EOS). Recently a number of preliminary reports about safety and effectiveness of MCGR have been published. We present a minimum of two years follow up of the MCGR treatment. All patients were treated in one center with the same protocol.Methods: 22 patients with EOS of different etiologies underwent primary surgical treatment with MCGR in double rod technique. There were 15 female and 7 male patients. Average age at surgery was 8.8 (range 4.6-14.3). Mean follow-up was 31 (24-46) months. Cobb angle changes, T1-T12 and T1-S1 length were calculated. Results were analyzed to measure correction of spinal deformity and gain in spinal length. Results:The mean preoperative curve measured 61° (40-96) and improved to 28° (11-53) (p<0.001) after surgery. At follow-up the Cobb angle was further reduced to 26° (11-64) (p=0.54). The T1-T12-as well as the T1-S1-length increased significantly (p<0.001). The average preoperative thoracic kyphosis decreased from 44° (-32-86) to 28° (9-50) after surgery, respectively to 35° (8-62) at time of FU. Four patients developed a junctional kyphosis. Three of them had to be revised. One patient developed a lumbar "adding on", one patient a deep wound infection and in another patient a screw pullout occurred that all required revision. Conclusion:The study supports that the MCGR is an efficient and safe technique to treat EOS. Morbidity and complications are less than treatment with conventional GR´s. After 2 years transcutaneous lengthening is still possible without loss of correction and autofusion has not yet been detected.

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The use of ultrasound in comparison to radiography in magnetically controlled growth rod lengthening measurement: a prospective study

Cited by 27 publications

References 11 publications

Does the external remote controller’s reading correspond to the actual lengthening in magnetic-controlled growing rods?

Does the external remote controller’s reading correspond to the actual lengthening in magnetic-controlled growing rods?

Analysing a mechanism of failure in retrieved magnetically controlled spinal rods

A Minimum of Two Years Results of Magnetically Controlled Growing Rods for Early Onset Scoliosis

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