Part 19
177. When the current of blood through the main trunk of the arteries of an extremity is cut off, the circulation is carried on by the collateral branches. This collateral circulation is more perfect, more active in young persons during the increase or growth of the body, than it is either at maturity or in the decline of life. The important point is not, however, alone referable to the time of life at which the continuity and permeability of the main trunk cease to exist, but to the nature of the disease or injury which has given rise to it.
When an aneurismal limb has been injected, on which an operation has not been performed, the collateral vessels have all been found larger and more fully shown than on the opposite side, although not to the same extent as in cases of a similar nature in which the operation has been done.
It is necessary that this enlargement of the collateral branches should lake place at an early period, because in many cases of aneurism the artery beyond or below the tumor is obliterated long before any operation is performed. The main supply of blood has been already cut off from the extremity, and the operation adds very little to the derangement of the circulation which has for some time taken place below the tumor.
When an operation has been successfully performed for aneurism, and the patient has died some time afterward, dissection has shown various arteries enlarged, both above and below the part where the trunk was obliterated by the ligature; and not only an enlargement of arteries, which, from their regularity have received names, but others have been developed not usually known to exist, or not of a size to be conveniently traced. These through their frequent anastomoses bring the blood at last into several large trunks, by which it is again conveyed to the original vessel below all and every obstruction which may have taken place; thus compensating by a circuitous route for the loss of the direct supply. The principal object of inquiry is, do these vessels always exist, or at what period of time do they begin to enlarge, so as to enable them to carry on the circulation, in the manner in which it is presumed to be done?--for few will assert that the enlargement of these particular collateral vessels was an accidental play of nature, and existed previously to the commencement of the disease or injury for which the operation was performed. On this point, the theory of the operation for aneurism and its applicability to wounded arteries appears to hinge; and, what is of more importance, on which the practice resulting from it depends.
Two distinct kinds of collateral circulation are at present acknowledged: one by direct large communicating arteries; the other through the direct medium of the capillary vessels inosculating with each other. Where direct communicating arteries exist, little subsequent change beyond enlargement takes place in them. It is otherwise with the indirect capillary vessels. When the radial or ulnar artery has been divided in the hand, the blood will not only flow readily from each end of the divided vessel, but equally red and arterial from both, the communication being through direct arterial branches from one vessel to the other. It will also be red and arterial if the division take place at the wrist, and may be so in the brachial; but if the femoral in the lower part of the thigh be wounded, the color of the blood issuing from the lower end of the artery, if any issue at all, will be _dark or venous_. It is so, because it has been obtained from the capillary arteries, which in this case being empty received blood by regurgitation from the veins, the valves of which when present do not prevent its reflux course. If a limb be injected and carefully dissected four or five days after a ligature has been placed during life high up on the principal trunk, the capillary vessels will be seen to be well injected; but few or none will be found large enough to admit of their inosculation being traced throughout. If another limb be injected and dissected, some sixty days after the ligature has been applied, a difference will be distinctly observed between the two preparations. In the latter, the capillaries will not appear to be so fully injected, but several larger and more tortuous vessels will be found in situations where they were not expected to exist; and the anastomoses of these one with another, generally by arches, may be traced to their communication with the principal trunk, both above and below the obliterated part. If an incision were made in the nearest pervious portion of the lower part of an artery in the thigh of a person who had undergone this operation, arterial blood would issue from it. The communication would have become direct by communicating branches, and the capillaries would have returned to their accustomed duties.
178. During the first twenty-four hours after the division of an artery such as the femoral, or the application of a ligature, the temperature of the limb is commonly diminished; after that period, and as the action of increase takes place, the temperature is usually from three to five degrees higher than in the opposite healthy limb. At the end of from eighteen to twenty-eight days, in a successful case, it is found to be equal in both.
It is asserted by some sanguine supporters of the all-powerful influence of the collateral circulation, that it is sufficient at all times, and under all natural circumstances, to maintain the life of the extremity. The practice of the Peninsular war proved the fallacy of this opinion in too many instances to admit of any doubt of its inadequacy to do so in the lower extremity after the division of the femoral artery, under ordinary circumstances. The fact of enlargement or of a new development of vessels having taken place after the commencement of disease or the reception of an injury, has been demonstrated by dissection, and it is through them the life of the limb is to be preserved; but time is required for their development. When a limb is lost through mortification, as the consequence of a division or obstruction of the principal artery, it usually takes place after the infliction of a sudden injury, in consequence of these collateral branches not having had time to enlarge.
179. The collateral circulation is therefore not the same, and is not in the same stage of preparation, in a limb suffering from a divided or wounded artery, as in one in which an aneurism has for some time existed; this is the reason why mortification is more common after wounded arteries than after operations for aneurism.
LECTURE X.
PROPER TREATMENT OF WOUNDED ARTERIES, ETC.
180. The due appreciation of the means adopted by nature and by art for the suppression of hemorrhage, as well as the proper treatment of wounded arteries, is owing to the surgery of the war in the Peninsula. They were suspected after the battles of Roliça, Vimiera, Oporto, and Talavera, but did not receive their complete development until after the battle of Albuhera. It was not until after that of Toulouse they were partially admitted; and it is only of late that they have been almost everywhere acknowledged, taught, and practiced.
Previously to the time of Mr. Hunter, the diseased or dilated state of the coats of an artery which constitutes an aneurism was, when it occurred in the ham, very often fatal. The operation of Anel, first performed in 1710, of cutting down to the artery, and placing a ligature upon it immediately above the dilated part, was not approved, and Mr. Pott, the great contemporary of Mr. Hunter, recommended in bad cases that amputation should be resorted to in the first instance; although Desault had succeeded, in 1783, in a case of popliteal aneurism, in which, after the manner of Anel, he had placed the ligature on the artery a little above the aneurismal swelling in the ham. Mr. Hunter’s contemplative mind, aided by his knowledge of anatomy and of disease, led him to believe that the ligature thus applied on the artery in the ham failed, because the vessel was unsound at that part, and was therefore incapable of taking on those healthy actions necessary for the obliteration of its canal above the ligature, which are known to take place when the artery is in a normal state. He concluded that this was sufficient to account for the failures, without especially taking into consideration the difficulty of applying the ligature in the ham immediately above the aneurismal sac, and of the probability of the sac suppurating when thus molested; an occurrence aiding materially in the necessity for the loss of the limb by amputation, performed then under circumstances of constitutional irritation, which would render it less likely to be attended with success.
From the consideration of these and other circumstances, Mr. Hunter was induced to propose, in 1785, that the ligature should not be placed on the artery near the tumor in the ham, but at a greater distance on the fore part or middle of the thigh, and Scarpa subsequently recommended it to be placed even higher--a recommendation which has been generally followed, and the spot now selected for this operation is at the lower part of the upper third of the thigh. This operation was therefore performed not only for aneurism, but improperly for a wound of the artery, not only in the ham, but even in the leg; it consequently failed in almost every instance of traumatic injury, thus rendering amputation necessary, which was generally followed by death.
181. The Hunterian theory implies:--
1. That the artery is in general sound at the part in the front of the thigh selected for operation, while it is usually unsound in the popliteal space behind, or in the ham, where Desault operated, and Anel recommended it to be done; that operation is now abandoned on the continents of Europe and America, as well as in England.
2. That a ligature can readily be placed upon it at a distance from the disease in the fore part of the thigh, and will usually be followed by success as far as concerns the obliteration of the artery immediately below the part on which it is applied.
3. That the artery being aneurismal, the collateral branches had begun to enlarge, so as to be better able to carry on the circulation, after the supply of blood to the lower part of the limb by the main trunk had been cut off.
4. That no branches of importance are usually given off between the ligature on the artery on the fore part of the thigh and the sac of the aneurism in the ham.
5. That if such branches were ever given off, and brought the blood from their collateral communications back into the main artery below the ligature, and thence into the sac, so as to renew its pulsatory movements, they would ultimately disappear, from the impelling force not being sufficient to prevent a gradual coagulation taking place, which would soon fill up the cavity of the sac, and thus prevent its further enlargement; at which stationary point a process of removal by absorption would begin and continue, until the diseased sac with its contents had diminished, if not entirely disappeared, leaving only a trace behind of its former existence, the process thus described being frequently assisted by a commencing obliteration of the artery immediately below the aneurism. The essential point in this theory, which has immortalized the name of Hunter in surgery, depends on the integrity of the aneurismal sac, which ultimately retains, as a general rule, subject to rare exceptions, any blood which may be brought into it, either by the collateral branches from above, or from below by what may be called regurgitation, until it has become coagulated, when the sac is so filled up that no more blood can pass into it to cause its further distention, or any ulterior evil.
This theory of Mr. Hunter, then so new, so beautiful in itself, was eagerly embraced by nearly all the civilized world; and surgeons were not content with applying it to cases of diseased or aneurismal arteries, to which it is especially applicable, but they extended it indiscriminately to cases of wounded arteries, to which the practice of the war in Spain proved it was inapplicable, and in which I have, since 1811, maintained it could only succeed as a matter of _accident_, not of principle.
182. The essential features of the theory opposed to Mr. Hunter, with respect to wounded arteries, and called mine, are:--
1st. That the artery at the wounded part is free from previous disease, and may be expected to take on those healthy actions which, after the application of a ligature, lead to the obliteration of its canal, and the consequent suppression of hemorrhage.
2d. That the circulation of the blood by the collateral branches is less free in a sound limb than in one which has suffered during several weeks from the formation of an aneurism.
3d. That this freedom of circulation is less in the _lower_ than in the _upper_ extremity, under all circumstances.
4th. That mortification of the foot and leg, and often of the whole limb, followed by the death of the person, is a common occurrence after a ligature has been placed high up on the artery in the thigh, in consequence of a wound; while it is not so common an occurrence when such operation is performed in the same place for an aneurism of several weeks’ duration. If the vein be also wounded, mortification is almost inevitable.
5th. That mortification of the hand and arm rarely follows the application of a ligature to the artery of the _upper_ extremity in any part of its course, however near the heart.
6th. That when the collateral vessels are capable of carrying on the circulation through the lower extremity, the _lower_ end of the divided artery bleeds _dark_ or _venous_-colored blood, while its _upper_ end bleeds _scarlet_ or _arterial_-colored blood. In the upper extremity, the color of the blood from the lower end of the divided artery is little altered--a consequence of the greater freedom of anastomosis, or of the freer collateral circulation in the upper extremity. Facts of the greatest importance in surgery.
7th. That whenever the collateral vessels are not capable of carrying on the circulation of a limb, mortification or death of the part ensues; and _that whenever this collateral circulation is sufficient to maintain the life of the limb, blood must pass into the artery below the wound, and must, as a general rule, pass up and out through the lower end of the divided artery, unless prevented by the application of a ligature, or by some accidental circumstance, forming an exception to the rule, but not the rule itself_.
8th. That the collateral branches are capable of bringing blood into the artery above the aneurismal sac and between it and the ligature, is admitted in the Hunterian theory, which blood the aneurismal sac receives, and usually retains. When the artery is a wounded artery, and the ligature is applied at a distance above the wound, blood is often brought into it below the ligature in a similar manner; but as there is _no aneurismal sac_ to receive and retain it, the patient bleeds perhaps to death, unless surgery come to his assistance.
9th. The presence of an aneurismal sac in one case, and its absence in the other, is the essential difference destructive of the Hunterian theory for the treatment of aneurism being applicable to that of wounded arteries.
10th. The processes for the natural suppression of hemorrhage are somewhat different in the upper and lower ends of an artery, and are less capable of resistance in the lower. This end frequently yields to the pressure of the blood regurgitating from below, and renews a bleeding which may have been suppressed for weeks, unless its closure has been rendered more permanent by the application of a ligature.
11th. The absence of the aneurismal sac renders the application of two ligatures absolutely necessary, one on each end of a divided artery, or one above and one below the wound, if the artery should not be divided; constituting the most essential feature of my theory, and the principal point to be attended to in the treatment of wounded arteries.
12th. This bleeding from the lower end of the vessel, which is more or less of a venous color, and issues in a continuous stream, may be restrained by compression properly made on the course of the lower part of the wounded artery; but in no instance should recourse be had to a ligature on a distant part of the artery above the seat of injury, until every other possible effort to arrest the hemorrhage from the lower end of the vessel has failed.
13th. The great principles of surgery to be observed in cases of wounded arteries, and which ought never to be absent from the mind of the surgeon, are two in number:--
1. That no operation ought to be performed on a wounded artery unless it bleed.
2. That no operation is to be done for a wounded artery in the first instance but at the spot injured, unless such operation not only appears to be, but is impracticable.
183. The means adopted by nature for the suppression of hemorrhage have been investigated by Celsus, Rufus, Galen, Œtius, etc., down to Dr. Jones, the most important English writer on this subject; but the methods of inquiry they all adopted appear to have been insufficient and unequal to the object in view. They bled an animal until he died, and then reasoned on the manner or means by which the bleeding was suppressed, when it was in fact arrested by death. It is obvious, then, that it is only when nature has not been interfered with, and the patient has not died from bleeding continued to the last moment, but has, on the contrary, lived some time after the hemorrhage has ceased, that the processes by which its suppression has been accomplished can be fairly investigated. These processes essentially depend on the size and variations of structure in an artery, which have been shown to be dissimilar in large and small arteries, and not even quite alike in the upper and lower ends of the same artery--facts which were elicited from observations made on men on the field of battle during the Peninsular war, and consequently not liable to error. It was then proved that arteries of moderate dimensions, such as the middle part of the femoral or the axillary, tibial or brachial, and particularly all below these in size, are capable, by their own intrinsic powers, when completely divided, of arresting the passage of the blood through them without any assistance from art, or from the surrounding parts in which they are situated. The establishment of this fact overthrew at once the theory which relates to the importance of, and necessity for, the sheath of the vessel, and the offices it performs in suppressing hemorrhage in vessels of this size, and in a great measure that supposed to be derived from the formation of an external coagulum, the _bouchon_ of the French.
184. When the femoral artery has been fairly divided in the lower part of the thigh, the patient has, in almost all the cases which have come under observation, either died without assistance, or the hemorrhage has ceased spontaneously. Having been thus arrested for twelve hours, the efforts of nature are usually sufficient to prevent its return from the _upper_, although not from the _lower_ end of the vessel; but then it is of _venous_ and not of _arterial_ color--a fact I first demonstrated, and which is now acknowledged to be of the greatest importance. The great evil to be dreaded in such cases is not from hemorrhage from the _upper_ end of the divided artery, but from the _lower_, and from _mortification of the foot_.
The _upper_ end of an artery retracts on being divided, and this retraction is accompanied by a contraction of the cut extremity of the vessel, which assumes the shape of the neck of a French wine-bottle or Florence oil-flask. The contraction is confined in the first instance to its very extremity, so that the barrier opposing the flow of blood is formed by this part alone. The contraction, however, goes on increasing for the space of an inch; it is usually filled up with an internal coagulum of a round, pyramidal shape, adhering firmly to the contracted end of the artery, loose at its apex, and extending frequently as far as the first collateral branch, but rarely under any circumstances beyond two inches; the very orifice of the artery on the outside being in a few days covered by a layer of a yellowish green-colored substance or fibrin, which indicates its situation in a remarkable manner. Some of these processes are continued even after the external wound has healed; the artery generally goes on diminishing and contracting as far as it is useless, so that of three or four inches, from one to two may be impervious, the remainder being contracted, although still permeable by a probe. An accompanying nerve, where there is one, would do the reverse, the cut extremity would become enlarged or bulbous, gradually diminishing as it is traced upward, until it regains its proper size.
The processes adopted by nature for closing the lower end of a divided artery of the size of the femoral at the inferior part of the thigh are somewhat different from those employed at the upper or opposite extremity. The retraction or contraction of the _lower_ end of a divided artery is neither so perfect nor so permanent as at its _upper_ end, and the small internal coagulum is in many instances altogether wanting, or very defective in its formation. The closure of the lower orifice being less perfectly accomplished than of the upper, it is the more likely to suffer from secondary hemorrhage, which may be distinguished from that from the upper end of the artery at an early period after the accident, by the _venous color of the blood, and from its flowing or welling out in a continuous stream, as water rises from a spring, and not with an arterial impulse_.
The retracting and contracting powers in the lower end of a divided artery are nevertheless considerable, and are sufficient in some cases to nearly close the lower end of the femoral artery when divided by amputation above the knee. When the femoral artery is cut across, the lower portion of the vessel is emptied by its last efforts, combined with the action of the capillaries. When the collateral circulation is powerful, blood soon regurgitates into the artery, but the force of the regurgitation can be in no proportion to that of the propulsion at the other or _upper_ divided end of the vessel, which will generally be able to resist this impulse, while the _lower_ one often opens and bleeds after the lapse of a few days. In all the cases I have had an opportunity of examining, in which hemorrhage had taken place from the lower end of the artery, the following appearances were observable after the interval of from four to five days.