History of the Orthopedic Screw

n guest editorial

Timothy T. Roberts, MD; Christoph M. Prummer, BS; Dean N. Papaliodis, MD; Richard L. Uhl, MD; Theodore A. Wagner, MD

ew inventions compare with the wheel—an elegant, simple Fdevice that has had a profound effect on human development. Perhaps worthy of comparison, the screw is a machine of simplicity and near-universal application; however, for all of its uses and ubiquity, few appreciate the story behind the screw’s evolution. Considered the father of the screw, Archimedes of Syracuse is widely regarded as having invented the screw in the third century BCE. His published treatises on geometry were a mathematical milestone.1 However, beyond mathematical theory, Archimedes’ discovery had a remarkable application. His water screw consisted of a long wooden pole that was 2 to 3 meters in 1 length; this core supported a continuous double or triple helical Figure 1: The water screw was used as a conveyer for transferring wa- thread of wood strips that were sealed with pitch resin. Wooden ter to higher ground. Image in public domain: http://etc.usf.edu/clipart/ planks placed lengthwise around its circumference completed 15000/15042/archimedean_15042.htm the tubular construct, which could rotate as a single piece. With 1 end submerged in low-lying water reservoirs, water screws provided a pulsatile lift of water, a process famously responsible Recently, similar designs of water screws have been pro- for providing irrigation to the Greek city of Alexandria.2 Some posed by archeologists to have existed in Mesopotamia as early surviving representations of the water screw depict an individual as the seventh century BCE. These cast bronze water screws are treader balanced atop the cylinder and running in place to spin thought to have had a rotating helix mechanism, which turned the massive helix. by hand crank within a stationary tube (Figure 1). Purportedly, they helped irrigate the Hanging Gardens of Babylon—one of the Seven Wonders of the Ancient World.2 Although the true origins of the water screw are disputed, it is clear that the first The authors are from the Department of Orthopaedic Surgery (TTR, application of the screw was for irrigation. Amazingly, over a DNP, RLU), Albany Medical Center, Albany, New York; and the Department millennium would pass before the screw was used for its more of Orthopaedic Surgery (TAW), Sports Medicine & Spine Surgery, and the Department of Neurological Surgery (TAW), University of Washington familiar purpose: a fastener. School of Medicine (CMP), Seattle, Washington. In the 15th century, shoulder-supported firearms such as The authors have no relevant financial relationships to disclose. Harquebusses were common among soldiers of Europe and Correspondence should be addressed to: Timothy T. Roberts, MD, Asia. These light, muzzle-loaded weapons contained match- Department of Orthopaedic Surgery, Albany Medical Center, 43 New Scotland Ave, Albany, NY 12208 ([email protected]). locks, which allowed for superior accuracy because operators no doi: 10.3928/01477447-20121217-02 longer had to relinquish a hand to light the chamber. However,

12 ORTHOPEDICS | Healio.com/Orthopedics n guest editorial

repeated firing of the weapon would quickly loosen the small nails used to fasten matchlocks to the stocks. Small screws were substituted for their superior holding power.3 However, despite their clear advantages, the complexities and high costs associated with producing screws made them an impractical option for most types of fixation. It was not until the 19th century that screws would be manufactured in industrial quantities and made avail- able for everyday purposes. By the late 18th century, European and American craftsmen had developed and patented effective screw-cutting lathes (Figure 2). The inventions created a rapid increase in threaded fasteners, and with the introduction of standardized thread forms, a highly mecha- nized industry evolved in which millions of screws were produced 2 per year by the mid-19th century. Accompanying the evolution of Figure 2: Screw-cutting lathe, circa 1870. Image in public domain: http:// standardized forms, self-tapping screws with gimlet points were runeberg.org/tektid/1871/0050.html introduced in 1832, eliminating the need for pilot holes.3 Similar revolutions occurred with the development of new alloys and drives, and with the development of the turret lathe in 1840, diminishing cifically to bone: a ratio of exterior diameter to core diameter of production costs established the ubiquity of screws. 3:2, not 4:3 as is typical of metal screws; a reduction of thread surface area to one-sixth that of metal screws because bone is ap- History of the Orthopedic Screw proximately one-sixth the strength of metal; and a buttress thread The 19th century saw similar revolutions in the field of ortho- design to replace standard V-shaped threads because buttress pedic surgery. In 1850, French surgeons Cucel and Rigaud per- threads had greater holding power.7 formed the first internal fixation procedure by reducing an olec- With retooled screws and the addition of compression plates ranon fracture with 2 transcutaneous screws fastened by string.4 (another of his creations), Danis was able to achieve precise ana- Perhaps more famously, German surgeon Carl Hansmann per- tomical fracture reductions with rigid fixation.8 This allowed for formed the first internal plate fixation using a removable steel both early mobilization of the patient and primary bone healing plate and nickel-plated screws in 1886.5 Hansmann’s screws were (Haversian remodeling) that characteristically lacked external pre-welded to his screwdrivers, and the driver handles remained callus formation. So impressive were the results that Swiss sur- attached to the plate and protruded through the skin upon fixa- geon Maurice Müller, himself one of Danis’ students, assembled tion. After 6 to 8 weeks, the entire construct was removed—often a team of fellow Swiss surgeons to study the process of bone a necessary second procedure given the lack of aseptic technique healing and the influence of rigid fixation on fractures. Meeting and the impurities inherent to 19th century metallurgy. first in Chur, Switzerland, in 1958, they called themselvesAr - By 1912, William O. Sherman, surgeon to the Carnegie Steel beitsgemeinschaft für Osteosynthesefragen (AO)—German for Company, published recommendations on the most effective the Association for the Study of Internal Fixation. “The AO was properties of orthopedic screws. Among his many recommenda- soon joined by additional surgeons, manufacturers, and metallur- tions—which concerned everything from alloy composition to gists. The influential group would subsequently develop the lag the width of drive heads—Sherman advocated self-tapping, fully screw, tension band wires, articulated tensioning devices, pow- threaded vanadium machine screws instead of the customary ered equipment, and specialized instruments for implant inser- tapered soft-steel screws that were intended for use in carpen- tion.4 In the same year as the AO’s founding, George Bagby and try.4 In addition, Sherman produced his own plate design, which Joseph Janes, surgeons at the Mayo Clinic in Rochester, Min- remained the international gold standard for 50 years until the nesota, published their design of a new “impacting” bone plate.9 advent of the AO screw. The American plate, which had a lower profile than many of its Despite significant advances in the principles of fixation and European counterparts, bore unique oval-shaped holes that al- the development of devices such as Sherman’s plates, orthope- lowed eccentrically placed screws to provide intrafragmentary dic screws remained relatively indistinct from their metal- and compression upon tightening.9 Their design, with relatively little wood-working counterparts. However, by the 1940s, many sur- modification, remains in use today. geons were advocating for the development of screws adapted Subsequently, research and innovation continued to change specifically to human bone. Most famously, Belgian surgeon the course of the orthopedic screw. From the introduction of Robert Danis6 proposed 3 key screw design features tailored spe- stainless steel in 1926 to the testing of titanium alloys in the

JANUARY 2013 | Volume 36 • Number 1 13 n guest editorial

1970s, screw strength and biological inertness improved to a As our understanding of biomechanics, medicine, and mate- point at which metal composition was no longer a significant rial science continues to evolve, so too will the role of the screw factor for potential screw pullout. Likewise, the introduction of in orthopedics. From Archimedes’ water screw to matchlock fas- Phillips and Woodrugg screw heads made slippage at the driver– tening and from Hansmann’s fortuitous fixation to dual-lead tita- head interface a rare event. Over the following decades, screw nium pedicle screws, innovation continues to drive the screw’s composition, thread count, shape, pitch, and diameter continu- progression, one revolution after another. ally advanced with designs optimized for a variety of bone types, qualities, and pathologies.7 References 1. Calinger R, Brown JE, West TR. Ancient mathematical zenith in the hel- Role in Modern Orthopedic Surgery lenistic third century B.C., II: Archimedes to Diocles. Calinger RS. ed. A Contextual History of Mathematics: To Euler. Upper Saddle River, NJ: Similarly to general orthopedics, research in spine surgery is Prentice Hall, 1999; 150-169. currently exploring the biomechanics of screws. Central study 2. Dalley S, Oleson JP. Sennacherib, Archimedes, and the water screw: the con- questions concern the role of techniques, such as tapping vs non- text of invention in the ancient world. Technology and Culture. 2003; 44:1-26. tapping, and the biomechanical qualities of screw features, such as 3. Rybczynski W. One Good Turn: A Natural History of the Screwdriver cannulation, tread depth, pitch, and single- vs double-lead threads. and the Screw. New York, New York: Simon & Schuster, 2000. In 1996, Chapman et al10 explored how factors such as screw 4. Klenerman L. The Evolution of Orthopaedic Surgery. London, United Kingdom: The Royal Society of Medicine; 2002. thread geometry, tapping, and cannulation affected the holding 5. Sauerbier S, Schön R, Otten JE, Schmelzeisen R, Gutwald R. The de- power of screws in cancellous bone. Using polyurethane models, velopment of plate osteosynthesis for the treatment of fractures of the they demonstrated that tapping a hole prior to screw insertion mandibular body: a literature review. J Craniomaxillofac Surg. 2008; reduced the maximum pullout strength by 8%. Tapping of a po- 36(5):251-259. rous material results in removal of excess supportive material, 6. Danis R. Théorie et Pratique de L’Ostéosynthèse.Paris, France: Masson; 1949. thus reducing the area of its interface with the screw threads. In 7. Sehlinger TE, Selingson D. History and development of the orthopedic addition, increasing the thread shape factor (the ratio of thread screw. Harvey JP, Games RF. eds. Clinical and Laboratory Performance depth to pitch) increases the pullout strengths. Therefore, can- of Bone Plates. Philadelphia, Pennsylvania: ASTM; 1994:2-9. nulated screws, which have a relatively low thread shape factor 8. Newman K. History of the AO: The first 50 years. AO Foundation Web to accommodate the central bore, have weaker pullout strength site. http://www.aofoundation.org/Structure/the-ao-foundation/about/ Pages/history.aspx. Accessed December 13, 2012. than noncannulated screws. 9. Bagby GW, Janes JM. The effect of compression on the rate of fracture In a similar study, the pullout strength of double-lead or fast healing using a special plate. Am J Surg. 1958;95(5):761-771. drive screws was compared with that of single-lead screws. 10. Chapman JR, Harrington RM, Lee KM, Anderson PA, Tencer AF, Using cadaveric thoracolumbar and lumbar vertebrae, Jacob et Dowalski D. Factors affecting the pullout strength of cancellous bone al11 were unable to find a significant difference between the pull- screws. J Biomech Eng. 1996; 118:391-398. out strengths of either lead type, despite the double-lead screw 11. Jacob AT, Ingalhalikar AV, Morgan JH, et al. Biomechanical comparison of single and dual-lead pedicle screws in cadaveric spine. J Neurosurg having a faster insertion time. Spine. 2008; 8:52-57.

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