Operations on the nervous system

Operations on the nervous systemOperations on the nervous system, as well as most others, treats diseases caused by inflammation, tumors, injuries, congenital defects, and some of un­known cause. For simplicity in presentation, the various operative procedures employed in the treatment of diseases of the neurological system may be presented here, regardless of the disease for which they are used.

Preoperative care in the surgical treatment of diseases of the nervous system may neces­sarily be most extensive, especially of the cen­tral nervous system. Many of the aforemen­tioned tests may be necessary to confirm ac­curate diagnosis. Concurrent disease and physio­logical disorders present as a result of the pri­mary disease require well-calculated controlling measures before operation. Surgery of this sys­tem is usually intricate and formidable.

Postoperative care, for similar reasons, must also be specifically and correctly executed. Con­tinuous care must be afforded to the posture, skin, and elimination. Rehabilitation after major neurological operations is often of major im­port and may require great persistency and determination on the part of the patient.

Craniotomy is the term applicable to any operation on the cranium. This is the proce­dure employed to gain entrance into the cranial vault for any underlying surgical disease. The incision through the scalp is made any place over the head where the disease has been local­ized, usually behind the hairline. The incision is designed to allow a flap of the scalp to be reflected off the cranium. The opening into the cranium is made by drilling holes (trephining) about the flap of bone to be removed and then cutting between the holes. The flap of bone is removed; the meninges are opened; the underlying disease is treated; the meninges are closed; the bone fragment is replaced; and the scalp wound is closed. Drains are frequently left in place to allow the serum or blood to escape from the cavity. Craniectomy also means removal of part of the cranium, essen­tially synonymous with craniotomy.

Lobectomy means the operative removal of a lobe of the brain. A lobe may be re­moved in part or in total; the extent of removal, of course, depends on the nature of the dis­ease to be ablated. When some vital areas are necessarily removed, sensory losses and paral­ysis are expected results. But again a slightly handicapped life is better than allowing a fatal disease to progress untreated.

Lobotomy is an operation on the frontal lobe of the brain for the purpose of disconnecting the communicating fibers of the lobe’s cortex from the lower tracts. It is noted that the frontal lobe is the personality center; it also interprets pain. Disconnecting it from its nerve pathways has been found useful in the treatment of certain psychotic states and for pain of disease which cannot otherwise be relieved. Lobotomy is accomplished by a hole drilled in the cranium and a cutting instrument passed through the lobe to sever its connec­tions. Several different techniques have been employed by entrance through the cranium or through the roof of the eye orbit. Lobotomy is also called leukotomy.

Topectomy is the operation on the nervous system wherein the cortex from the frontal lobe is removed. This is indicated in the same conditions as is lobo­tomy; namely, to disconnect the personality center in psychotic states or disconnect pain interpretation in uncontrollable pain. Craniot­omy gains entrance to the frontal lobes, and the specific areas of cerebral cortex are removed by electric cautery and excision.

Ventriculostomy means draining of a ven­tricle. This is indicated in cases of hydrocepha­lus where there is an obstruction to the usual cerebrospinal fluid flow, and the CSF accumu­lates by blockage of the path to its absorption sites. With this operation a drainage pathway from the ventricle is devised for drainage to another site of excretion. A small plastic tubing is placed from a ventricle to another cavity, such as the mastoid sinus, the kidney, the ab­dominal cavity, or a CNS space of a lower level. Such drainage devices may alleviate hydro­cephalus in infants for many months or years.

Laminectomy is operation on the nervous system through which entrance is gained into the spinal canal. The lamina is the part which is cut through, hence the name of the operative procedure; the spinal process and laminae are removed baring the spinal cord and its cover­ings. This may be a part of an operation to gain entrance to any portion of the spinal canal for any purpose. In some cases the spinal cord coverings will require opening and in some not. In hemilaminectomy only the lamina on one side is removed. Either type may be performed on one vertebra or on several adjacent ones. Opening into the spinal canal may be necessary for the removal of tumors, after in­juries, or vertebral disc disorders. On comple­tion of the procedure the heavy spinal muscles are closed over the wound as well as the skin and other soft tissues.

Chordotomy is the term applied to the op­eration of cutting the pain tract in the spinal cord. This is done with laminectomy, most often at the lower neck level. The operation is useful in relieving pain which cannot otherwise be controlled in incurable diseases. The tempera­ture sense fibers are in the same tract as the pain fibers, so temperature sensation may be lost as well. But no other senses or functions are impaired.

Tractotomy is the operation of severing a nerve tract. It may be performed on the spinal cord with laminectomy, or in the brain with craniotomy. This procedure is applicable to certain pain pathways in cases of uncontrollable pain. It is especially useful in the case of severe pain of the fifth cranial nerve (tic douloureux).

Rhizotomy is sectioning of the spinal nerves at their union to the spinal cord. It is useful in certain cases of pain in which case the sen­sory roots are severed and in cases of spastic paralysis wherein the motor roots are cut. The effect of rhizotomy is limited to the segment supplied by the severed spinal nerve root.

Sympathectomy is the operation of severing and removing portions of the sympathetic trunk. It finds its greatest usefulness in diseases of the arteries, such as high blood pressure and other diseases where the arteries remain in spas­tic constriction. Disconnecting this automatic nerve supply to the vessels allows them to dilate and become more flaccid; the circulation is thereby improved. In the case of involvement of the vessels of the lower extremity, sympa­thectomy is performed at the mid-trunk level, most often by incision through the abdomen. One side or both may be treated. In most cases sympathetic block will be done beforehand to anticipate the value of the operation. In the case of high blood pressure sympathectomy may be employed in both the chest and abdominal levels. Entrance into the chest is gained from the back by incision on either side of the spinal column. In various other less common condi­tions sympathectomy has been advocated.

Presacral sympathectomy is the operation on the nervous system for removal of the network of sympathetic fibers in the pelvic region. These nerve filaments lie over the front of the lower spinal column, i.e., the sacrum. This procedure may be indicated in cases of severe menstrual pain (dysmenor­rhea), in instances of internal menstrual bleed­ing (endometriosis), and occasionally in other types of intractable pelvic pain. The approach is by incision through the lower front of the abdomen.

Splanchnicectomy is a operation on the nervous system for inter­ruption of the sympathetic nerve supply of the blood vessels and organs within the abdominal cavity. This operation entails removal of seg­ments of the splanchnic nerves, either by ap­proach through the lower chest or the upper abdomen, or both. It has been found useful in certain infrequent cases of diseases of almost all the abdominal organs, and in high blood pressure.

Vagotomy. The vagus nerve (Xth cranial nerve) car­ries the parasympathetic supply to the abdominal organs; disrupting this supply is useful in the treatment of some intra-abdominal diseases, especially peptic ulcer.

Operations on peripheral nerves may be indicated in a variety of conditions and many different techniques are employed:

Neurotomy is a general term for operation on a nerve. Neurectomy designates removal of a nerve; nerve section is the cutting of a nerve. These may be performed for uncontrollable pain in a region, or for spastic paralysis. The region rendered senseless or paralyzed is limited to that which the nerve supplies.

Nerve resection is the removal of a portion of a nerve with reconstruction by suturing the stumps together. This is performed in cases of tumors of nerves.

Neurolysis is the freeing of a nerve from ab­normal attachments, such as constricting scar tissue, tumor, or excessive bone in areas of pre­vious fractures. Nerve transposition may be part of the procedure.

Nerve injections are useful for treatment in destroying the function of a nerve in certain dis­eases. A solution, usually alcohol, is instilled into the nerve through a needle. This destroys the nerve’s ability to conduct. The nerve often slowly regenerates, and in some cases a repeat procedure is required. Usually, however, the loss of function is permanent. A preliminary diag­nostic nerve injection with a local anesthetic is most often done to predict the results of thera­peutic injection.

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