NEUROSURGERY ST 240 Divisions of the nervous system Central nervous system (CNS) the brain and the spinal cord Peripheral nervous system (PNS) external to the brain and spinal cord from their roots to their peripheral terminations. This includes any plexuses through which the nerve fibers run. Divisions of the Nervous System Spinal nerves - 31 pairs of nerves which carry (send) messages to & from the spinal cord Spinal Nerve Plexus & Important Nerves Meninges Any membrane; specifically, one of the membranous coverings of the brain and spinal cord. Dura mater- a tough, fibrous membrane forming the outer covering Arachnoidea - A delicate fibrous membrane forming the middle. In life, its smooth external surface is closely applied (but not attached) to the internal surface of the dura mater, with only a potential space (subdural space) intervening. Between the Arachnoidea and Pia mater is Subarachnoid space Pia mater - A delicate vasculated fibrous membrane firmly adherent to the capsule of the brain Lumbar puncture -needle puncture made into the subarachnoid space; usually between 3&4 or 4&5 lumbar vertebrae performed for various reasons Meninges and Related Structures Indications for neurosurgery To remove pathological lesions To relieve pressure on brain or spinal cord due to disease or injury To relieve pain To relieve injured or diseased peripheral nerves To treat congenital anomalies Carpal tunnel release - decompression of the medial nerve Carpal tunnel syndrome -painful disorder of the wrist & hand in which pressure is on the median nerve at the point at which it goes through the carpal tunnel Cranial nerve - 12 pairs of nerves which carry messages to & from the brain Ventricle -one of the cavities of the brain; produces CSF Cerebrospinal fluid (CSF) -watery fluid protecting the brain & spinal cord Automatic nerves -that part of the nervous system which represents the motor innervation of smooth muscle, cardiac muscle, and gland cells. It consists of two mutually antagonistic components: the sympathetic and parasympathetic parts A-V malformations -thin-walled vascular channels that connect arteries and veins without the usual intervening capillaries; may give rise to intracerebral hemorrhage Brain abscess -localized collection of pus in the intracranial region Craniosynostosis -premature ossification of the sutures of the skull Decompression -the removal of pressure Stereotaxis -accurate placement of a probe, needle or electrode in a specific location in the brain Diagnostic tools Digitalized angiography (Cerebral angiography) - x-ray are taken after injection of a contrast medium into the intracranial vessels, helps visualize aneurysms, tumors, or other vascular lesions Echoencephalography -ultrasonic waves used to detect brain tumors; used to detect brain tumors, hematomas, swelling or abscesses Pneumoncephalography -air is injected through a lumbar puncture into a subarachnoid space & x-rays are taken to reveal the outline of the ventricular system Pericranium -fibrous membrane surrounding the cranium; periosteum of the skull Peripheral nerves nerves which connect the brain or spinal cord with peripheral receptors or effectors Sella turcia -a concavity in the superior surface of the body of the sphenoid bone which houses the pituitary gland Pituitary tumor -benign or malignant tumor that presses on the optic chiasm & impairs vision & may cause symptoms of acromegaly Meningocele -congenital hernia with the meninges protruding through opening of the skull or spinal column Sciatica pain -severe pain in the leg along the course of the sciatic nerve felt at back of thigh running down the inside of the leg Mechanical methods of hemostasis Bone wax Scalp clips Cottonoids to 2x3 Monopolar and/or bipolar electrocoagulation Ligaclips Chemical methods of hemostasis Oxycel Topical thrombin Gelfoam Surgicel Avitene Special considerations of neurosurgical procedures If the patients hair is shaved, it is considered part of patients personal belongings, bagged & set back to room with patient. Surgeon may assist with draping Surgical technologist keeps rongeur clean for continued use. CT Scan depicting Brain Tumor Craniotomy -incision into the cranium to treat intracranial disorders Pin Fixation Device Headrests -used to securely position or fixate the skull during a cranial or cervical spine operation Craniotomy Surgeon places scalp clips for hemostasis along the outside edge of the incision. Scalp flap is turned back & covered with a moist sponge & sterile towel. Surgeon strips peritoseum from the bone with periosteal elevator Raney Scalp Clip Applier Scalp Clips Placed/Muscle Cut Bur Holes Surgeon makes 2 or more bur holes with either a hand-or-power drill (ANSPACH drill with perforator) Technologist must be ready to irrigate the drilling site to counteract heat buildup & to remove bone dust. Surgeon saws skull bone between bur holes with cranial tome Retractors Placed/Bone Rongeured Surgeon separates the dura mater from the bone by a dura separator (Penfield #3 dissector) Surgeon uses rongeur, such as a Kerrison, to enlarge the bur holes. Have bone wax ready Penfield Dissectors #1#2 #4 #3 Surgeon lifts the skull flap off the dura mater with 2 periosteal elevators & controls bleeding with bone wax. Skull flap is covered with moist sponge and a sterile towel & protected in saline moistened sponges into a basin. (bug juice: saline & antibiotic solution) Dura Opened and Retracted/Cerebellar Hemispheres Exposed Surgeon grasps dura edges extends the incision with Metzenbaum scissors. At this point, technologist needs to prepare traction sutures on fine needle holders (dolphin head) Ryder needleholders) Surgeon protects brain surface with moist cottonoid strips. Craniotomy closure Surgeon closes dura mater with fine absorbable suture.(4-0 nylon P3 popup) (possibly 3 pkgs of 8 or more) Skull flap is replaced and fixated with plates and screws Surgeon removes scalp clips & sutures muscle (Vicryl 2-0 or 0 CT2 or 3 or UR6, subcutaneous tissue), skin - sutures of choice (usu. staples) Craniotomy closure Cranioplasty -repair of a skull defect resulting from trauma, malformation, Or a surgical procedure; involves covering the defect with some type of prosthetic material, such as metal, methyl methacrylate, silicone rubber, or bone & cartilage If tumor has grown into bone, cranioplasty is done Trephination Bur holes (trephination) -Removal of a circular piece (button) of cranium Remove a collection of fluid beneath the dura mater Tap a ventricle to relieve pressure Aspirate a brain abscess & instill antibiotics Locate & drain a subdural hematoma Cranio -prefix pertaining to the skull Craniectomy - incision into the skull & removal of bone Craniotomy Subdural Hematoma Hematoma -tumor or swelling that contains blood Craniotomy Circle of Willis Intracranial aneurysm -localized abnormal dilation of a blood vessel in the skull may be due to a congenital defect or weakness of the wall of vessel Aneurysm Clips -device placed on an aneurysm to prevent hemorrhage yet allow collateral blood flow Temporary Clip Permanent Clip Clip Applier Different Types of Aneurysm Clips Ventriculoatrial Shunt: Hydrocephalus Hydrocephalus -increase accumulation of cerebrospinal fluid within the ventricles of the brain resulting from an interference with the normal circulation & absorption of the fluid Shunt operations -performed to treat hydrocephalus by diverting excessive cerebrospinal fluid from cerebral ventricles to other body cavities where the fluid can be absorbed Ventriculoperitoneal Shunt VP shunt: Hydrocephalus Ventriculoatrial Shunt: Hydrocephalus Nucleus pulposus - the center cushioning of gelatinous mass lying within an intervertebral disc (or disk) Spinal Cord & Spinal Nerves Intractable pain - pain that cannot be easily relieved, such, as that occurring from certain neuro plastic invasions EX: herniated disc, lamina expansion) Spinal Neurosurgical procedures Laminectomy -removal of one or more vertebral laminae to expose spinal cord; commonly performed to treat one of the following: herniated disc (nucleus pulposus) spinal cord tumor meningocele compression fracture or dislocation spinal cord injuries due to trauma Lamina -the flattened part of either side of the arch of a vertebra Lumbar Myelogram with Herniated Disk (degeneration) Myleography -contrast medium is injected into the subarachnoid space of the spinal canal to visual a herniated disc, tumor, or other abnormality Herniated disc - rupture of the fibrocartilage surrounding an invertebral disc, releasing the nucleus pulposus that cushions the vertebrae above & below with resulting pressure on the spinal nerve roots & pain Lumbar Laminectomy Lumbar Laminectomy, Disectomy Posterior lumbar discectomy with interbody fusion- PLIF Excision of one or more herniated lumbar intervertebral discs & the placement of bone grafts between the vertebrae to fuse them together; internal fixation can be implanted; lateral fusion may also be done ( Laminectomy must be done ) Anterior lumbar discectomy with interbody fusion ALIF Anterior excision of one or more herniated lumbar intervertebral discs & the placement of bone grafts between the vertebrae to fuse them together; internal fixation can be implanted posteriorly; lateral fusion may also be done Lateral Cervical X-ray Removal of anterior cervical disc with fusion ACD,ACF Excision of one or more herniated cervical intervertebral discs & the placement of bone grafts between the vertebrae to fuse them together. Anterior Cervical Fusion An anterior cervical fusion involves 2 operative sites. Both operative sites, the neck & iliac crest are prepped & draped. Thyroid drapes at neck folded up above hip. Lower half of body also draped. The bone graft commonly taken from iliac crest Surgeon removes disc with pituitary ronguer & fine curettes.