occupational hazard to the pregnat orthopedic surgeon

8/2/2019 Occupational Hazard to the Pregnat Orthopedic Surgeon

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Orthopaedicforum

Occupational Hazards to the PregnantOrthopaedic Surgeon

Roxanne R. Keene, MD, Diane C. Hillard-Sembell, MD, Brooke S. Robinson, MPH,

Wendy M. Novicoff, PhD, and Khaled J. Saleh, BSc, MD, MSc, FRCS(C), MHCM

Abstract: The number of female orthopaedic residents and orthopaedic surgeons has increased substantially. Con-

cerns have been raised regarding the effect of the work environment on the health of the female orthopaedic surgeon

and her fetus or neonate. Occupational risks, and specifically risks to the pregnant orthopaedic surgeon, are becoming

an important issue in medicine. Such risks include exposure to methylmethacrylate (MMA), anesthetic gases, blood-

borne pathogens, radiation, emotional stress, and physical stress. Awareness of and knowledge about such exposures

are needed for the pregnant orthopaedic surgeon to make informed decisions about her occupational exposures and to

be proactive about her own and her childs health.

The percentage of women in medical schools in the U.S. increasedfrom 11.1% in 1970 to 48.3% in 20071, and the percentage ofwomen in orthopaedic residency training programs increasedfrom 0.60% in 1970 to 12.0% in 20092. According to Katz et al.,the rates of preterm labor, preterm delivery, low birth weight, andabruptio placentae are higher in female physicians compared withthe general female population3. Although pregnancy complicationscan also result from other factors, such as having children laterin life, complications during early pregnancy can be attributed toexposure to chemicals, gases, radiation, and infectious diseases4.

This paper will review the occupational hazards associ-ated with orthopaedic surgery. The hazards associated withmethylmethacrylate (MMA), anesthetic gases, blood-borne path-ogens, radiation, emotional stress, and physical stress are ofspecific concern for the pregnant orthopaedic surgeon. Be-

cause female orthopaedic surgeons are consistently exposed tothese risks5, a review and discussion of the available literature willbe presented to allow the practicing female surgeon to makeinformed decisions about her prenatal and postnatal exposures.

Potential Occupational Hazards

Methylmethacrylate (MMA)Methylmethacrylate (MMA) is commonly used as the cementfor fixation of orthopaedic prosthetic devices. The U.S. Envi-ronmental Protection Agency recommends exposure to a time-weighted average of no more than 100 parts per million (ppm)of MMA over an eight-hour work day6.

Developmental effects following MMA exposure havebeen documented in animal studies. Singh et al. calculated theacute toxicity and lethal dose of MMA in rats to be approximately

Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party i n support of any

aspectof thiswork.One or more of theauthors, or hisor herinstitution, hashad a financial relationship, in thethirty-sixmonths prior to submissionof thiswork,

with an entity in the biomedical arenathatcould beperceived to influence or have the potential toinfluence what is written in this work. Also, one ormoreof the

authors hashad another relationship, or hasengaged in another activity, that couldbe perceivedto influence or have the potentialto influence what is written

in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.

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J Bone Joint Surg Am. 2011;93:e141(1-5) d http://dx.doi.org/10.2106/JBJS.K.00061


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1.33 mL/kg7. On the basis of these calculations, pregnant ratsreceived an intraperitoneal injection of MMA at one-tenth,one-fifth, or one-third of the acute lethal dose. Dose-related in-creases in gross and skeletal abnormalities of the fetus and areduction in fetal weight at birth were observed7. A similar studyby McLaughlin et al. evaluated the effect of MMA vapor onpregnant mice8. The MMA exposure was markedly greater thanthe recommended occupational exposure (1330 ppm comparedwith 100 ppm averaged over an eight-hour day). However, theproportion of normal compared with abnormal fetuses and thenumber of fetal deaths did not differ significantly compared withunexposed mice8. McLaughlin et al. also studied the MMA con-centration that resulted from MMA mixing. MMA exposure wasgreatest in the operating room during the beginning of the mix-ing process, going from 280 ppm to


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recommends that she avoid breastfeeding and find a replace-ment feeding that is sustainable and safe20.

RadiationOrthopaedic surgeons rely heavily on the use of radiography, in-cluding intraoperative fluoroscopic imaging. This use of radiog-raphy has the potential to expose the pregnant female surgeonand her fetus to dangerously high levels of radiation. Most of theavailable data on the effects of radiation on the human body,including on the fetus, were obtained by studying the 1945 atomicbomb survivors from Hiroshima and Nagasaki. This group in-cluded approximately 2800 pregnant women, 500 of whom re-ceived a radiation dose of >500 to 1000 milliGray (mGy)21.

According to the National Council on Radiation Protec-tion and Measurements (NCRP), the maximum radiation expo-sure to the fetus before harm occurs is 0.05 Gy22. Potential sideeffects of radiation exposure of >0.05 Gy to the fetus includeprenatal death, growth restriction, small head size, severe mental

retardation, organ malformation, and childhood cancer23. Theseside effects depend on the radiation dose and on the develop-mental stage of the conceptus at the time of exposure23. Becausethe embryo or fetus is more sensitive to radiation at certainstages of development, radiation risks decrease as the pregnancyprogresses23. Prior to two weeks of gestation, the embryo is verysensitive to radiation, and a dose of >0.1 Gy (equivalent to ap-proximately 75 fluoroscopy uses or extremity radiographs) maycause death of the embryo23. However, if the embryo survives,radiation-induced non-cancer health effects are uncommon. Aslong as the fetal dose remains 6%childhood cancer rate and a >55% lifetime cancer rate25.

Thus, diagnostic radiation doses are associated with asmall risk of cancer, but no evidence for an increase in mentalretardation, congenital malformations, or microcephaly has

been shown to be associated with the occupational exposurethat a pregnant orthopaedic surgeons child would typicallyreceive over the course of the pregnancy. Most radiology expo-sures without protection to the pregnant orthopaedic surgeonschild result in fetal absorption of


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Although emotional stress poses a substantial healthhazard for many pregnant women and their fetuses, theabovementioned stressors in the orthopaedic work environ-ment create an increased occupational risk for pregnantorthopaedic surgeons. A study by Walsh et al. found that res-idents could deal with these emotional stressors better ifthey had more flexibility in their rotations and if they hadnecessary allowances, such as regular breaks and privacy, whilebreastfeeding36.

Physical Stress

The specialty of orthopaedic surgery inherently involves a levelof physical exertion greater than that seen in many other med-ical or surgical subspecialties. Furthermore, the demands ofon-call trauma treatment can be associated with long hoursof standing, lifting, and bending. These occupational factorsmay be of special concern for the pregnant orthopaedic sur-geon because of the potential for work-related musculoskeletal

symptoms and adverse pregnancy outcomes37-45.The physiological responses of pregnant women and

their fetuses have been shown to be related37-40. DiPietro founda bidirectional relationship between fetal behaviors and mater-nal physiological responses and noted that fetuses had a higherlevel of motor activity if the pregnant women had greater anx-iety or stress37. Likewise, when the fetus moved, there was a risein the maternal skin conductance37. Physiological changes inpregnant women include increases in the body core tempera-ture, metabolic rate, and heart rate and stroke volume, as wellas musculoskeletal changes37,38.

The interactions between pregnancy and exercise havebeen well studied but not well understood37-40. Gavard and

Artal found that exercise had a positive effect on pregnancyoutcomes by increasing cardiovascular fitness; in addition,exercise reduced maternal weight and the occurrence of ges-tational diabetes and preeclampsia38. Similarly, DeMaio andMagann recommended that pregnant women participate insubmaximal aerobic exercises, resistance training exercises,and/or aquatic exercises for thirty minutes on most days ofthe week39. They found that brief submaximal exercise at70% of maximum aerobic capacity did not affect the fetalheart rate39. In comparison, Lereim and Ro found that vari-ous orthopaedic procedures resulted in an aerobic workloadof 20% to 30% of the maximum aerobic capacity40. Thus,submaximal aerobic exercise is beneficial for pregnant ortho-

paedic surgeons in order to maintain the aerobic capacitynecessary to continue working.

Several studies have examined the effect of work activityduring pregnancy41,42. Croteau et al. conducted a case-controlstudy to evaluate whether occupational conditions were asso-ciated with preterm delivery, defined as birth of the infantbefore thirty-seven weeks of gestation41. Of the occupationalconditions present from the onset of pregnancy, two physicalfactors were significantly associated with preterm delivery: ademanding posture (bending, squatting, or raising the armsabove shoulder level) for three hours or more per day andwhole-body vibrations41. However, no statistical difference in

the rate of preterm delivery was found in women who workedlong hours or who engaged in prolonged standing41. Hatchet al. found that long hours of work (>40 hours per week) wereassociated with reduced fetal growth, with infants of womenwho had worked long hours late in pregnancy having a lowergestation-adjusted birth weight42.

Musculoskeletal changes occur during pregnancy, andthe effect of these changes on work-related musculoskeletalcomplaints may be magnified in the orthopaedic surgeon43.The musculoskeletal changes during pregnancy are predomi-nantly related to alteration of the center of gravity, weight gain,the effect of circulating hormones on ligaments, and fluid re-tention. Low back pain occurs in as many as one-half of allpregnant women44. As a pregnant woman assumes a position ofhyperlordosis, this shift in load distribution theoretically gen-erates increased stress on the intervertebral discs, facet joints,and ligaments44.

Adjusting occupational conditions for working pregnant

women to result in shorter work hours, more frequent sitting,and improved body posture when sitting has been advocated toameliorate low back pain45. In order to better incorporate theserecommendations into her daily life, a pregnant full-time or-thopaedic surgeon should be educated regarding these modi-fications and should be proactive in implementing thesepreventive measures, starting in the first trimester40,41,45.

Summary

Although male and female surgeons face similar occupationalrisks in the work environment, the effects of these risks on apregnant orthopaedic surgeons fetus or neonate make her sit-uation unique. Whether it is exposure to MMA, anesthetic

gases, blood-borne pathogens, radiation, or stress, the femaleorthopaedic surgeon should know about how her occupationalrisks prior to, during, and following pregnancy might affect notonly her health but her childs health.

The number of female orthopaedic residents has increased33% from 2001 to 20081. As the number of female surgeonscontinues to increase, improved awareness of the unique occu-pational risks to pregnant orthopaedic surgeonsand a proac-tive approach to prevent or minimize such risksare imperativefor the well-being of the mother and her child.

Roxanne R. Keene, MDDiane C. Hillard-Sembell, MDBrooke S. Robinson, MPHKhaled J. Saleh, BSc, MD, MSc, FRCS(C), MHCMDivision of Orthopaedics, Department of Surgery,Southern Illinois University School of Medicine,701 North 1st Street, Springfield, IL 62702.E-mail address for K.J. Saleh: [email protected]

Wendy M. Novicoff, PhDUniversity of Virginia School of Medicine, P.O. Box 800159 HSC,Charlottesville, VA 22908

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occupational hazard to the pregnat orthopedic surgeon

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