As in Part 1, I'll include a number of references in this article. Most will be to either canon or Wiki articles giving more detail on some topics than I can include here. I also wish to thank Panteleimon Roberts, Danita and Nimitz Lover for their off Bar input.
For some things, there are no good substitutions.
As I noted at the end of Part 1, only a limited amount of suture material came through the Ring of Fire (RoF). Some is at the physicians' offices, some at the veterinarians' offices, and possibly some at the nursing home. Dr. Ellis or Dr. McDonnell might have a couple of spools of black surgical silk stashed with old office equipment. Because of the war and the change in medical conditions, this small supply will rapidly be used up. I don't know what stocks of plain (unflavored, unwaxed) dental floss will be available at the RoF, but the floss is fine enough and limp enough to thread through eyed needles, as well as strong enough and has a good enough "hand" (the ability to be securely knotted) to act as an impromptu suture material once sterilized.
Up-time, we have a wide variety of suture materials,[i] but down-time the Grantville medical community's options will be limited, at least until material sciences catch up. It's interesting to remember that thread sizes were standardized before specific sutures were in regular use, with size 0 being the smallest thread that could be spun with early-nineteenth century technology. As suture materials advanced, smaller and smaller threads and filaments were made, requiring more and more zeros to indicate the sizes. While up-time sutures are available down to 11-0 size (used for corneal surgery and requiring the use of an operating microscope), the most common sizes used range from 3-0 to 6-0, which is as fine as most human hairs. Size 0 and even #1 sutures are most often used to hold chest tubes in place, or provide closure (when passed through buttons) in very obese abdomens. The use of smaller sutures, along with earlier removal, leads to less scarring, especially on the face.
The first absorbable sutures available down time will be processed from sheep gut. This material was used in Our Time Line (OTL) through the 1990s and is similar to the strings used for violins, violas and tennis racquets. In OTL, two forms were used, plain and chromic. The difference between the two was a treatment with chromic salts that makes the chromic-treated (essentially tanned) material last about twice as long as the plain, at an increased risk of serious inflammation. Gut is best sterilized with iodine solutions, a technique developed in 1906 in OTL. The synthetic absorbable suture materials (polyglycolic acid derivatives)[ii]will probably appear around the same time as nylon and polyethylene sutures do, as the same kind of advancements of the organic chemical industry is needed, and sutures done with the synthetics heal much better than those done with gut. This is especially true in plastic surgery and where absorbable sutures are needed near vascular repairs.
Early down-time non-absorbable sutures will include braided silk, spun cotton, and silver wire. Linen thread may also be used, although it is stiffer than cotton, and causes substantial inflammation[iii]. Both cotton and linen are more flexible and actually stronger when wet, which helps make them useful for suturing. Point of use sterilization will consist of wrapping the suture material around a soft core like a rubber tube and boiling it for twenty minutes. A sample should be weight tested for tensile strength before use.[iv] Braided polyester will probably be the first up-time suture material redeveloped, as it will be usable with the same kind of eyed needles as the silk and cotton.
A fair chance exists that some of the thinnest suture material for a few years will actually be iodine treated horsehair. This is the closest thing available to fine monofilament sutures and is soft enough to thread through the eye of the smallest needles.
Up until the early 1950s in OTL, all surgical needles had eyes to hold the thread, just like the common sewing needles from which they were derived. Despite modifications of the eyes to allow the suture material to lay flat along the tail of the needle, the bulk of the doubled thread causes more trauma to the patient's tissues than the simple passage of the curved needle.
In the early 1950s, a technique to swage the hollow butt end of the needle around the bitter end of the suture material was developed. This resulted in an "atraumatic" needle/suture set, which is much gentler to the tissues than the older method.
One reason for developing the swaged-on units was that monofilament suture materials were too stiff to lay properly in the grooves of an eyed needle. Fine (5-0 or smaller) monofilament suture material, needle drivers, and small swaged-on needles are all necessary preconditions for the development of vascular and cardiac surgery, as was noted in Part 1 of this series. Monofilament suture materials' stiffness does mean that it is more difficult to tie those materials securely. Despite their extra stiffness, monofilament sutures have advantages over the braided forms, both in reduction of tissue damage, reduction of tissue irritation, and reduction in the chances of post-operative infections. Over time, the braided or spun materials allow bacteria to follow the suture track deep into the tissues. Monofilament sutures decrease the risk of this effect. Both nylon and polypropylene may be available before 1640, and but probably not by the time stainless steel needles should be available-around 1636-37. These polymers are easily drawn out to fine monofilaments, especially with the expected down-time technological advances between 1631 and 1640. Thus, braided polyester and silk will probably be the first suture materials to benefit from swaged on needles as a result.
Up-time, swaged-on suture materials come in a variety of precut lengths, generally from 18 inches (45 cm) to 36 inches (90 cm). They are normally double wrapped and sterilized by radiation from Cobalt 60 or other high gamma radiation source. Steam sterilization will work for all of the natural materials except gut, and most of the synthetic materials. A caveat is that heating the monofilament materials while they are coiled may cause a "set," which makes the suture material much more difficult to deal with.
Needles in a Needle Stack[v]
Suture needles themselves come in a bewildering variety of sizes, shapes, and points, many of which are more or less interchangeable. The vast majority of needles up-time have a curve because this allows the needle to pierce flesh with a simple twist of the hand holding the needle driver. This also allows the tissues to meet together in a more natural position. While simple, tapered (conical) pointed needles will have some utility, most often there will be a triangular point with a cutting edge stretching along the inside (cutting) or outside (reverse cutting) of the curve. Straight needles are rarely used, being generally much larger (employed with the hand and not a needle driver), and reserved for situations where that is a feature and not a drawback. One example is closing the wound around a chest tube and securing that tube in place.
Stainless steel has already been mentioned as being the critical material for the development of instruments, suture needles, and orthopedic fixation wires. These three items will be the major driver for the first "laboratory" amounts of stainless steel, as even these small quantities of stainless will be useful. As other material sciences develop, it will be useful for hypodermic and intravenous (IV) injection needles and as supporting needles when intravenous catheters are re-introduced. As supplies increase in quality and quantity, other uses, including as staples for closing the skin (usually done one staple at a time) and for automatic stapling devices for bowel resections[vi] which place up to seventy small staples at a time, and for use in orthopedic plates, screws, intramedullary rods and prosthetic devices to replace hips and knees. Stainless steel will replace silver for closing traumatic gaps in the skull, and stainless steel wire will provide the extra strength needed to reinforce bones that have been cut or splintered, including the sternum (breastbone) after chest surgery. Eventually, exotic alloys and titanium will replace stainless steel for most of the prosthetic devices, but this will probably not happen until the 1650s at the earliest.