Perils of Radiation


PERILS OF (IONIZING) RADIATION

In spine surgery, CT imaging is used to build a model of the patient’s anatomy.  This model is used for navigational purposes. Recently, the use of CT imaging based navigation in spine surgery has significantly increased.

CT scans for diagnosis and navigational assistance during spine surgery may expose a young patient to excessive radiation.

Multiple CT scans increase incidence of cancer in children
Studies show that individuals who have had multiple CT scans before the age of 15 were found to have an increased risk of developing leukemia, brain tumors1, and other cancers2 in the decade following their first scan.

Girls are at higher risk of cancer development
Solid cancer risk is high for girls with 1 case projected to result from every 270 to 800 spine scans, depending on age3.

Radiation doses are high for adolescent trauma patients with spinal injuries
Imaging studies of adolescents with spinal injuries received a median cumulative effective dose of 18.89 mSv (range 0–86.87 mSv), equaling to that of adult trauma patients and nearly 3 times that of pediatric trauma patients4.

Surgery to correct scoliosis necessitates higher amounts of radiation
The intraoperative radiation exposure for placement and confirmation of posterior instrumentation in patients with adolescent idiopathic scoliosis (AIS) with an average of 11 levels fused ranges from 8 mSv for navigation to 16 mSv for navigation and confirmation5.

 

Patients receive 3 times higher amounts of radiation with CT-based navigation than with fluoroscopy.

Type of surgery

Dose measurement Intraoperative CT scan (mSv) C-arm (mSv) Ratio
Pediatric deformity6 Per acquisition 1 0.3 3.3
Spinal instrumentation7 Per level 1.087 0.393 2.8
Unstable spine fracture8 Per level 2.7

(range 1.6 to 5.7)

 

0.84

(range 0.6 to 1.08)

3.2

 

The use of computed tomography (CT) has increased significantly over the last two decades.  In 2011, 85 million CT scans were performed in the US, with 5% to 11% of these scans being performed on children.  Although CT imaging provides improved diagnostic capabilities, its use comes with risk.  CT delivers ionizing radiation doses of 100 to 500 times higher than conventional radiography1.  This may increase the incidence of cancer, especially in young children.  According to Dr. Miglioretti’s et al retrospective study, each year, 4 million pediatric CT scans of the head, abdomen/pelvis, chest or spine are projected to induce 4,870 future cancers in the US.

Dr. Miglioretti et al determined this projection through the evaluation of the use of CT for children younger than 15 years of age from 1996 to 2010 and 744 CT scans performed between 2001 and 2011.  A total of 4.9 million child-years were observed within six health care systems.

Repeated exposure to ionizing radiation in young children has led to an incidence of cancer in adulthood according to Dr. Simony et al.  Between 1983 and 1990, Dr. Simony reviewed radiation data of 211 adolescent idiopathic scoliosis female patients and interviewed 159 of those patients 25 years after treatment.  The average total radiation exposure was 1.58 mSv, and an average of 16.3 x-rays was taken during treatment.  9 patients developed cancer, mostly breast (3) and endometrial (4).  The incidence of cancer was shown to be 17 times higher than the incidence of 0.25% in an age-sex matched cohort from the Danish Cancer Society Annual Report.

All navigation methodologies, including robotic surgery, rely extensively on pre-operative CT scans to enable intra-operative navigation.  These scans deliver ionizing radiation to the patient doses that are several multiples of magnitudes higher than normal x-ray and intra-operative c-arm.

 

DSG Solution

DSG Technology can minimize the amount of radiation exposed to the patient from a 25% to 54% reduction in fluoroscopic (C-Arm) images 9-11.

 

References

1Pearce MS et al. Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. Lancet. 2012 Aug 4;380(9840):499-505. doi: 10.1016/S0140-6736(12)60815-0. Epub 2012 Jun 7.

2Mathews JD et al. Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians. British Medical Journal 2013 May 21; 346:f2360

3Miglioretti DL1 et al. The use of computed tomography in pediatrics and the associated radiation exposure and estimated cancer risk. JAMA Pediatr. 2013 Aug 1;167(8):700-7. doi: 10.1001/jamapediatrics.2013.311.

4Lemburg SP et al. Cumulative effective dose associated with radiography and CT of adolescents with spinal injuries. AJR Am J Roentgenol. 2010 Dec;195(6):1411-7. doi: 10.2214/AJR.10.4616.

5O’Donnell C et al. Comparative radiation exposure using standard fluoroscopy versus cone-beam computed tomography for posterior instrumented fusion in adolescent idiopathic scoliosis. Spine (Phila Pa 1976). 2014 Jun 15;39(14):E850-5.

6Dabaghi RA et al. Comparison of Effective Dose of Radiation During Pedicle Screw Placement Using Intraoperative Computed Tomography Navigation Versus Fluoroscopy in Children With Spinal Deformities. J Pediatr Orthop. 2015 Apr 14. [Epub ahead of print]

7Mendelsohn D et al. Patient and surgeon radiation exposure during spinal instrumentation using intraoperative computed tomography-based navigation. Spine J. 2015 Dec 10. pii: S1529-9430(15)01673-3. doi: 10.1016/j.spinee.2015.11.020. [Epub ahead of print]

8Lee CY et al. Intraoperative computed tomography navigation for transpedicular screw fixation to treat unstable thoracic and lumbar spine fractures: clinical analysis of a case series (CARE-compliant). Medicine (Baltimore). 2015 May;94(20):e757. doi: 10.1097/MD.0000000000000757.

9Bai Yu-Shu, Yun-Fei Niu, Zi-Qiang Chen, Xiao-Dong Zhu, Liu Ka Po Gabriel, Hee Kit Wong, and Ming Li. “Comparison of the Pedicle Screws Placement Between Electronic Conductivity Device and Normal Pedicle Finder in Posterior Surgery of Scoliosis.” Journal of Spinal Disorders and Techniques 26.6 (2013 ): 316-320. Print.

10Chaput Christopher D., George Keri, Samdani Amer F., Williams John I., Gaughan John, and Betz Randal R.. “Reduction in Radiation (Fluoroscopy) While Maintaining Safe Placement of Pedicle Screws During Lumbar Spine Fusion.” Spine 37.21 (2012): E1305-E1309. Print.

11Defino Helton, Williams John, Fernando da Silva Herrero Carlos, Betz Randal, Powell David, George Keri, Gaughan John. “Does The Use Of Dynamic Surgical Guidance Assist With Accurate Pedicle Screw Placement In Patients With Osteoporosis Or Osteopenia?” 2015. 15e Congresso Brasileiro de Coluna. SpineWeek meeting, 2016. Singapore