Clinical Surgery in General - part 5 ppt

17 PREPARATIONS FOR SURGERY oesophagus) or damage to trachea or lungs during ear, nose and throat (ENT) procedures. 2. Operator hazard: usually the operator is not exposed to laser beams, but if you are accidentally exposed, it is frequently your eyes or skin that are damaged. Always wear eye protection since some laser beams will penetrate, and be focused on, the retina. Corneal burns or cataract formation have also occurred with less penetrating beams. Safety measures 1. There should be a laser protection advisor (LPA) to consult on the use of the instruments throughout the hospital and to draft local rules. 2. A laser safety officer (LSO) should be appointed from the staff of the appropriate department using each laser. This person may well be, for example, a senior nurse and will have custody of the laser key. 3. Everybody using the laser should be adequately trained in its use and be fully cognizant of all safety precautions. 4. There should be a list of nominated users. 5. A laser controlled area (LCA) should be established around the laser while it is in use, with control of personnel allowed to enter that area. The entrance should be marked with an appropriate warning sign, usually incorporating a light that illuminates while the laser is functioning. 6. While in the laser controlled area adequate eye pro- tection, appropriate to the type of laser in use, must be worn. The laser should not be fired until it is aimed at a target, and usually there is an audible signal during laser firing. 7. The laser should be labelled according to its classifi- cation. Lasers in classes 3a, 3b and 4 should be fitted with a key switch and the key should be kept by a specified person. The panels which constitute the side of the laser unit should have an interlocking device so that the laser cannot be used if the panels are damaged. There are various safety features that are required by way of shutter devices and emergency shut-off switches. Foot-operated pedals should be shrouded to prevent acci- dental activation. Medical lasers require a visible low power aiming beam, which may be an attenuated beam of the main laser, if this is visible, or a separate class 1 or 2 laser, such as helium/neon. The laser must be regularly maintained and calibrated. 8. Environment: reflective surfaces should be avoided in the laser controlled area. However, matt-black surfaces are not necessary. Adequate ventilation must be provided and should include an extraction system to vent the fumes produced. These fumes are known as the 'laser plume'. Key point • Pay particular attention to avoiding fire. Class 4 lasers ignite dry drapes or swabs. Damp drapes effectively stop carbon dioxide laser beams. Fibre optics Flexible instruments Fibre optics have undoubtedly made an immense impact on patient management. There is little evidence, however, that the instruments that incorporate fibre optics neces- sarily reduce mortality. Their value is in allowing accurate diagnosis and assessment of, for example, upper gastro- intestinal bleeding or oesophageal obstruction. Most hollow viscera or tubes, even very narrow ones, may now be inspected. Diagnostic and therapeutic procedures can be performed under clear vision, such as exploration of a ureter for tumour or stone, or subfascial ligation of incom- petent perforating veins. Thin fibreoptic instruments are integral to the development of minimal access surgery, such as 5 mm telescopes used for retrieving bile duct stones. In the 1950s, Professor Harold Hopkins of Reading University, UK, developed the earlier work of John Logie Baird, the inventor of television, to further the design of fibreoptic bundles, which could not only transmit a pow- erful light beam but also, when suitably arranged, deliver an accurate image to the viewer. In the 1960s, urological instruments were developed incorporating multiple flex- ible glass-fibre rods. Each fine fibre rod is constructed of high quality optical glass and transmits the image, or light beam, by the process of total internal reflection. This principle allows light to travel around bends within the fibre. Each fibre is only 8-10 (um in diameter, and to achieve the principle of total internal reflection it must be coated with glass of low refractive index, to prevent light dispersion. Many such coated fibres are bound together in bundles which can bend. For light transmission, fibres may be arranged in a haphazard manner (non-coherent). For clear-image transmission, the fibres must be arranged in a coaxial manner (coherent) (Fig. 17.3). The following are examples of currently available flexible endoscopes utilizing fibreoptic light bundles: • Oblique (for endoscopic retrograde cholangiopancre- atography (ERCP) and end-viewing gastroscopes • Laryngoscope • Bronchoscope • Fibreoptic sigmoidoscope and colonoscope • Cystoscope (pyeloscope) • Choledochoscope • Arterioscope. 190 OPERATING THEATRES AND SPECIAL EQUIPMENT 17 (a) Fig. 17.3 (a) Non-coherent fibre bundles for light transmission. (b) Coherent fibre bundles for viewing. Reproduced from Ravenscroft & Swan (1984) by permission of Chapman & Hall. Each instrument has similar design principles incorpor- ating the following: • Coherent fibre bundles for high quality visual image transmission • Non-coherent fibreoptic bundles for light transmission • A lens system at the tip and near the eyepiece of the instrument • A proximal control system to manoeuvre the tip of the instrument and also to control suction and air/water flow • Channels for blowing air or carbon dioxide and water down the instrument, and for suction - the latter doubles as a biopsy channel • A wire guide incorporated to control tip movement, which takes place in four directions, each usually allowing a deformity of greater than 180° movement • A cladding, consisting of a flexible, jointed construc- tion, covered by a tough outer vinyl sheath. Figures 17.4 and 17.5 show the basic structure of a typical endoscope, and Figure 17.6 shows the tip of an instru- ment, illustrating the lenses for light transmission and viewing, a suction channel, which should be large so it can be used in the presence of gastrointestinal haemor- rhage, and a small nipple directed over the lens, to enable the wash solution to clear the lens of debris. Light sources should emit a powerful beam and the intensity is usually 150 W. Many light sources employ a halogen bulb, which needs to be fan cooled. Rigid endoscopes Optical systems in rigid endoscopes also employ the prin- ciple of total internal reflection, but there are several lens systems in addition. The objective lens systems are nearest the image, and the relay lens systems are nearer the eye- piece of the rigid instrument, through which the observer Fig. 17.4 Basic design of a fibreoptic endoscope. Reproduced from Ravenscroft & Swan (1984) by permission of Chapman & Hall. Fig. 17.5 Further details of the basic design of a fibreoptic endoscope. A, endoscopic 'umbilicus'; B, suction pump; C, air pump; D, water reservoir; E, endoscopic insertion tube; F, biopsy port; G, suction button; H, air/wash button; I, endoscope control head; J, combined suction biopsy channel; K, water channel; L, air channel; M, combined air/water port. Reproduced from Ravenscroft & Swan (1984) by permission of Chapman & Hall. 191 tt forcible distortion, dropping and, particularly, of crushing from biting by patients' teeth; always insert the peroral endoscope through a suitable mouth gag. Broken fibres appear as black dots when viewed through the instrument. Fig. 17.6 The top of an end-viewing fibreoptic instrument. A, forceps raiser; B, wash jet; C, image guide; D, light guide; E, biopsy/suction channel. Reproduced from Ravenscroft & Swan (1984) by permission of Chapman & Hall. views a rectified and magnified image. Light is transmit- ted through a cable of non-coherent fibres or liquid elec- trolyte solution. Vision is through coaxial fibres which direct the light coaxially through a lens system in the rigid tube. Some of the longer lenses are made of high quality optical glass and act as a single large optical fibre for image transmission. Examples of rigid instruments are: • Cystoscope, urethroscope, pyeloscope, ureteroscope • Choledochoscope • Laparoscopes. The lenses at the far end of the instruments vary to allow different fields of view and minimize peripheral field distortion. Care of fibreoptic instruments 1. They must be properly cleaned and disinfected before use. Debris may block channels and make suction and insufflation of air and liquid difficult. After use, the instruments should be cleaned internally by utilizing one of several automatic cleansing machines, and externally with a suitable detergent solution. 'Q-tips' may be employed to clean lenses. Instruments should be soaked for at least 5-10 min between patients, often in a 2% gluteraldehyde solution, although 70% alcohol and low molecular weight povidone-iodine are alternatives. 2. In order to avoid instrument damage, endoscopies are usually performed in dedicated units under expert care. Damage is more likely to occur when a variety of people handle and clean instruments. Guard against Key point Ensure that only competent and careful people use and care for these expensive and valuable instruments. Autologous cell salvage With recent anxieties over transmitted disease, expense, religious views and the occasional scarcity of blood, autol- ogous (blood derived from the same individual) blood transfusion may be used. The advantages are consider- able: it avoids blood-related disease transmission, trans- fusion reactions, immnunosuppression and the need for grouping. A rapidly obtainable supply is available. The blood is collected via a sucker from the wound site, anti- coagulated, filtered and then passed through a washing phase, using saline. Washing removes all but the red cells, which are concentrated to an acceptable haematocrit and then reinfused. This technique is of particular use in car- diothoracic, vascular and orthopaedic surgery, especially when the loss of blood is expected to exceed 1 litre. It is a safe procedure provided you follow the rules. As a rule, do not use blood contaminated with septic fluids and malignant cells. Never use blood contaminated with bile, gut contents, meconium, urine or amniotic fluid. Cell salvage cannot be used if the blood is likely to mix with fluids which would lyse red cells, such as water, hydrogen peroxide, alcohol, povidone-iodine antiseptic, fibrin glue or antibiotics that are unsuitable for parenteral use. The alternative is predonation. Cryosurgery (syn. cryotherapy or cryocautery) Any application of an instrument that touches tissue at an extreme of temperature produces cell death. Cryosurgery (Greek kryos = frost) is the freezing of tissue to destruc- tion. Although cells are destroyed at -20°C, they may recover at higher temperatures than this. After freezing, the destroyed tissue sloughs off and reveals a clean, granu- lating base. The treatment is relatively pain free and minimizes blood loss. The object is to destroy abnormal tissue and preserve adjacent, healthy areas. You achieve this by producing an ice ball at the tip of a cryoprobe (Fig. 17.7). You must watch the size of the resulting ice ball, to control the volume of tissue destroyed. The size of 192 OPERATING THEATRES AND SPECIAL EQUIPMENT 17 Fig. 17.7 An ice ball at the tip of a cryoprobe. Reproduced by permission of Eugene A. Felmar, Santa Monica Hospital Medical Center, USA. the lesion produced by cryosurgery is related to the tem- perature at the tip of the ice probe, the size of the tip and the number of freeze-thaw sequences. The size of the iceball increases until the heat loss at the edge of the iceball is too small to permit further freezing of adjacent tissues. The size of an iceball and the extent of destruction can then be increased by a further freezing sequence. As a rule, allow the iceball to spread 2-3 mm into healthy tissue to ensure adequate destruction of the diseased area. Inevitably, freezing a wart on the sole of the foot is less Fig. 17.8 Cross-section of a cryoprobe tip, illustrating the Joule-Thompson principle. Reproduced by permission of Eugene A. Felmar, Santa Monica Hospital Medical Center, USA. critical than reattaching a retina. Various probe tips are available for the different tasks demanded of cryosurgery. Principles of therapy According to the Joule-Thompson principle, when gas expands, heat is absorbed from the surrounding matter. The simplest example of this is spraying ethyl chloride vapour on skin, which, as it releases gas, subsequently freezes. With a cryoprobe, however, the liquid gas, usually nitrogen or carbon dioxide, is sprayed against the inside of a hollow metal probe. The gas then expands in the tip and freezes the tissue on contact (Fig. 17,8). Cell injury with cryotherapy 1. Immediate phase: ice crystals form in the cell, rupturing the cell membrane. This is most effective with rapid freezing at greater than 5°C s- 1 . 2. Intracellular dehydration: results in increased and toxic levels of intracellular electrolytes. 3. Protein denaturation: occurs in the lipoprotein structure of the cell membrane, nucleus and mitochondria. 4. Cellular hypometabolism: results in enzyme inhibition. Later in the course of injury there is also a loss of blood supply, causing tissue necrosis, and the resultant slough, before separation, protects the tissues deep to the injury. When the slough separates it leaves a clean ulcer. As nerve endings are susceptible to cold injury, painful lesions can be rendered insensitive. Also, the treatment is not particularly painful for the patient, and local analgesia is usually unnecessary. Adjacent neurovascular structures are relatively safe, as collagen and elastic tissue resist freez- ing. Thus, the advantages of cryotherapy are that it is a rela- tively pain-free and simple method of destroying tissue, usually leaving clean wounds, often with a reasonable scar. The disadvantages of the technique are that frozen tissue cannot be analysed histologically, and thus this method of treatment is unsuitable for any lesion for which you will require microscopic examination. It may some- times be difficult to gauge the exact penetration in the depth of the tissues treated. Thus, its use may be limited in curative treatment of malignancy, and is of value in pal- liation. Occasionally there is some bleeding, and later dis- charge after the slough separates following, for example, cryosurgical treatment of haemorrhoids. Clinical applications Since there are various shapes of probe tips, a reasonable variety of therapeutic applications is available. To ensure that freezing occurs, there must be a wet contact 193 17 PREPARATIONS FOR SURGERY to allow thermal conductivity. Two or three freeze-thaw cycles may be applied, with overlap of the treated areas if necessary. Examples of the clinical application of cryosurgery include the following: • Proctology: haemorrhoids and warts • Gynaecology: cervical erosions and warts • Dermatology: warts, low grade skin cancers, herpetic lesions • ENT: pharyngeal tonsillar remnants, carcinoma of the trachea, hypophysectomy • Ophthalmology: cataract extraction, glaucoma, detached retina • Neurosurgery: Parkinson's disease and cerebral tumours. Microwave ablative techniques You can use this technique on prostatic tissue, for benign prostatic hypertrophy, and the endometrium - usually for menorrhagia. The principle of treatment depends on the transfer of energy by the use of microwaves, which are a form of electromagnetic energy. Penetration depths depend on the electrical properties of the tissues, and the frequency of the electromagnetic wave. Conventional microwave kitchen ovens use energy at a frequency of around 2.45 GHz, which, in tissue with a high water content, would penetrate to a depth of approximately 18 mm. The microwave applicator has a strength of 9.2 GHz, uses 30 W of power and the treatment takes about 2—4 min. For endometrial ablation performed under general or regional anaesthesia, the cervix is dilated, the length of the uterine cavity is measured, and the calibrated and non-adherent probe is inserted to the fundus and withdrawn with side-to-side movements. Temperature measurement is monitored and probe temperatures of 80-95°C are reached to ablate the endometrium to a depth of 4-6 mm. Interestingly, with this range of endoluminal temperature, there is little serosal heating. This treatment may be safer than endometrial resection and hysterectomy, as there are fewer complications. The few serious complications of the procedure have been endometritis, cervical splitting during dilatation, and in one instance perforation of a retroverted uterus. There are other methods of endometrial ablation. This is merely used as an example of microwave energy, and you should not confuse it with radiofrequency endometrial ablation (RAFEA). Ultrasound Diagnostic Ultrasound probes provide a valuable aid during abdomi- nal surgery to identify tumour deposits and anatomical landmarks such as blood vessels. Clear guidance may be obtained as to the resectability of tumours or the presence of clinically undetected metastatic deposits. Hand-held ultrasound probes can be employed at open operations; for example, small islet cell tumours of the pancreas may be located accurately. Small laparoscopically inserted instruments are also used for staging and anatomical purposes when per- forming operations with minimal access (see Ch. 23). They compensate to some extent for the inability to palpate structures. During laparoscopic cholecystectomy, a probe may be used not only to identify structures but also to locate common bile duct stones. Surgical aspirator There are various ways in which the liver parenchyma may be dissected with minimal blood loss. One of these is the CUSA (Cavitron UltraSonic Aspirator). The oper- ating titanium tip of the instrument vibrates longitudi- nally at 23 000 oscillations per second (23 kHz). The instrument works by converting electromagnetic energy to mechanical movements. An electrical coil wrapped around metal laminations sets up a magnetic field, thus causing the metal to vibrate. The fine hollow tip of the instrument disrupts solid parenchyma by its fine vibra- tions and the heat this generates. When debris is shed, it is mixed with fluid jetting from the instrument and the mixture is sucked away. More solid and fibrous struc- tures, such as ducts and blood vessels, are not disrupted, and may then be clipped with haemostats or ligated. Not only may this instrument be useful for open, solid parenchymal dissection, but it may also be used during laparoscopic dissection of the gallbladder or mobiliz- ation of the colon. Ultrasonic harmonic scalpel Increasing use of this instrument attests to its ability to aid safe, careful dissection with less bleeding than accompa- nies diathermy dissection. The instrument works by transforming electrical energy from a generator into mechanical energy through a set of piezoelectric ceramics, which are contained in a hand piece. The mechanical energy is passed through a disposable element, often a hook or clip, which vibrates at approximately 55.5 kHz. The energy spreads a small distance around the instru- ment tip. The extreme vibrations fracture internal cellular bonds. Proteins are denatured and reorganize to form a sticky coagulum. Vessels up to 2 mm in diameter can be safely divided. Soft tissue coagulation occurs at tempera- tures below 100 S C, producing minimal charring and smoke or vapour. 194 OPERATING THEATRES AND SPECIAL EQUIPMENT 17 A real advantage of this equipment is that it reduces the number of instrument changes during an operation, such as haemostats, staples, scissors and ligatures. It is a mul- tifunctional instrument facilitating precise cutting with minimal lateral thermal damage. It does not use electric- ity, with all its potential risks. It was introduced in the mid-1990s and is used in, for example, the specialities of gastrointestinal surgery, gynaecology, urology and oto- laryngology. Do not use it for incising bone or for contra- ceptive tubal ligation. The harmonic scalpel system is valuable for soft tissue incisions where you require good haemostasis and minimal thermal injury. The instrument can be used for open or laparoscopic surgery as an adjunct to, or substitute for, diathermy, lasers or steel scalpels. Argon beam (plasma) coagulator (Valleylab) This instrument offers a thermal technique for sealing blood vessels from large, raw areas such as the cut surface of the liver and kidney. It works by passing an electrical current through what is called a 'plasma arc', created in argon, not air. When electrons are fired into the gas, ion- ization occurs, which in turn produces further electrons. These then ionize more gas and a 'domino' effect takes place. The plasma thus consists of free electrons, positive ions and neutral atoms (Fig. 17.9). The coagulator can be valuable in controlling bleeding resulting from coagulation disorders. It applies a direct, high frequency electric current to the target tissue without direct contact. The effect is well defined and has a self- limiting depth of penetration. There is minimal charring of the treated tissues, producing a thin and flexible eschar. As a result there is a minimal tendency for rebleeding. Because there is no contact between the instrument and the coagulated area, the coagulum is not pulled off and so is unlikely to rebleed. The tissue which has been treated by this technique develops a spongy appearance and enlarges the tissue surface. X-rays Preoperative findings Key point • It is negligent and dangerous to start an operation without having available all the radiological results and films (see Ch. 4). Place essential films, with the names, date and hospital number checked, correctly orientated, on the screen so you can refer to them as necessary. Tissue target Fig. 17.9 Argon-enhanced coagulation. This is in effect a bipolar diathermy with the pathway from the active electrode to the tissue completed through argon gas. An arc or beam is produced with argon gas from the nozzle, which makes contact with the target tissue. Electrons are fired into it from the electrode, producing ionization, which, in turn, produces further electrons; these produce more ionization and so generate a domino or self-generating effect. The plasma arc is thus partly converted into positive ions and free electrons - in effect passing a current without instrument contact. The conventional active diathermy electrode adheres to the coagulum and may pull it off as it is withdrawn. The argon beam carrier overcomes this disadvantage, as there is no physical contact with the tissue coagulum. Capital letters indicate argon gas; capital letters such as +A+ indicate ionized argon, o- indicates electrons. It overcomes the disadvantage of adherence of the active diathermy electrode to the tissue coagulum. Intraoperative procedures Diagnostic help. An example is on-table cholan- giography. Use sufficiently dilute contrast medium to allow one to 'see through' the common bile duct on the film. Fill the biliary tree adequately to show the main intrahepatic ducts as well as the common bile duct. Contrast medium is heavier than bile and tends to gravi- tate to dependent ducts. If the ampulla is patent, contrast medium flows into the duodenum, which is clearly recog- nizable by its mucosal pattern. Remember to put a 20° 195 17 PREPARATIONS FOR SURGERY lateral tilt on the table to eliminate the overlap of contrast on the vertebral column. Intraoperative angiography can be performed follow- ing a steady intra-arterial injection, and provides ade- quate films. Adverse reactions to modern contrast media when the patient is generally anaesthetized are very rare. Therapeutic use. Imaging using fluoroscopy may facil- itate therapeutic procedures. It is valuable for simple pro- cedures, including fracture reduction. Complex techniques include interventional uroradiology. Many of these tech- niques can be performed either in the operating room or in the X-ray department; facilities for fluoroscopy are usually better in the X-ray department, but asepsis is better in the operating theatre. X-ray machines are difficult to clean and are potential sources of crossinfection. In specialist centres, dedicated complex X-ray rooms may be organized in a fashion similar to operating theatres, or the facilities for radiology may match those in the X-ray department. Key points • Discuss problems beforehand with a radiologist and subsequently report the outcome and anatomical findings. • Give adequate warning to the radiographer of the need for X-rays in the operating theatre. Equipment This is more likely to be mobile than static. The use of image intensification avoids the need for you to allow your eyes to become dark-adapted. Mobile image inten- sifiers for use in the operating theatre are mounted on a small C-arm. The table top must be radiolucent, with space beneath as well as over the table for the X-ray tube and the image intensifier. If films alone are required, the table top must have a 'tunnel' that admits the X-ray cas- sette beneath the patient. Alternatively, the cassette may be draped in sterile towels. This may be necessary, for example, if you need to carry out intraoperative mesen- teric angiography on bowel lifted out of the abdomen at laparotomy. For a small field, the X-ray cassette can be placed on the image intensifier itself to obtain a film. Some modern machines can produce dry silver images directly from the television monitor. Biplane screening is not usually available in the oper- ating theatre. The mobile C-arm is, nevertheless, quite versatile and the effect of 'parallax' can be used to aid the judgement of depth. Mobile X-ray sets operate from designated 13 A sockets that are on a separate ring main from other essential equipment. Modern mobile sets use 'sparkless' switching to avoid the danger of igniting inflammable gases. It is desirable to keep the mobile X-ray machine in the operating suite. X-rays and the law X-rays, as well as scalpels, become weapons of assault if not used with care. Medical staff clinically directing examinations employing ionizing radiation are required to have obtained a certificate demonstrating that they have received some training in radiation protection. This should eventually be included in the undergraduate cur- riculum. Equipment must be regularly serviced and cali- brated, and 'local rules' applied. In case of doubt, contact the hospital radiation protection supervisor. Key points • Only radiologists, radiographers or others holding an approved qualification may direct exposures. • Look after yourself, other staff in the theatre and the patient. Use the lead aprons. Safety • Remember that the patient 'scatters' the X-ray beam. The inverse square law applies, so staff should not be unnecessarily close. Be aware of the screening time and record it. • Do not X-ray the abdomen of pregnant patients unless absolutely necessary. Establish the date of the last menstrual period before the patient is anaesthetized. Key point • Take an interest in imaging, as 'a picture is worth a thousand words'. Microscopes Spectacles have been available for nearly 700 years and the compound microscope for about 300 years, but it was only 70 years ago that a microscope was used in theatre, and only 30 years ago that its use became more widespread. Although they were introduced very gradu- ally to the operating theatre, they have now become indis- pensable in a wide variety of surgical fields. They offer improved views of the surgical field, more precision, greater flexibility, and less trauma to delicate tissues. They provide good stereoscopic appreciation of depth, through a narrow surgical approach, much smaller than your own unaided interpupillary distance allows. 196 OPERATING THEATRES AND SPECIAL EQUIPMENT 17 A Swedish otolaryngologist, Nylen, introduced his monocular microscope in the surgical treatment of otosclerosis in 1921. A year later his chief, Professor Holmgren, used a binocular microscope for the same condition. In 1925, Hinselman used a microscope for colposcopy, but aside from this for three decades otolaryngologists alone continued to use microscopes. In Chicago, Perritt used a microscope for ophthalmic surgery in 1950, and Zeiss started to mass produce their MiI surgical microscope in 1953. Clinical applications then expanded: Jacobson in vascular surgery in 1960; Kurle in neurosurgery and Burke in plastic surgery in 1962. With the increased employment of free transfer flaps and microvascular anastomosis, the use of the operating microscope reaches several surgical disciplines. Features of an operating microscope • Eyepieces provide an adjustment for interpupillary dis- tance and each eyepiece has a range of 5 dioptres. • Binocular tube may be straight or inclined. • Beam splitter allows for the connection of extra viewing tubes for observation and assistance. It also makes the use of still and video cameras possible as teaching aids. • Magnification system. Magnification is available as a galilean system, variable in steps (e.g. x6, x10, x25, x40), or as a zoom system. • Objective lens allows the working distance to be altered by changing lenses with variable focal lengths. For example: / = 150,175, 200 for ophthalmology and plastic surgery / = 250 for otology and vascular surgery / = 250 or 300 for gynaecological tubal surgery / = 300 or 400 for neurosurgery / = 400 for laryngoscopy. • Depth of field. The stereoscopic depth of field is less at higher magnification. Focus at higher magnification first, then reduce to the working magnification so as to have the best focus at the centre of the depth of field. • Light. A powerful coaxial halogen light is incorporated in the body of the microscope. Oblique light is available for eye surgery. Instruments used with microscopes Each speciality has developed microsurgical instruments for its own needs; however, the following basic instru- ments are common to many specialities: • Spring-handled needle holder such as Borraquer or Castrovieso, ophthalmic. • Spring-handled microscissors, straight or curved. The straight are for cutting vessels and the curved for cutting tissue and thread. • Jewellers' or watchmakers' forceps in a wide variety. • Microsurgical clips such as Scoville-Lewis, or fine Heifetzs neurosurgical clips, can be used for vessel anastomosis. • Microelectrode: monopolar or bipolar cautery is necessary. • Suture material: (1) blood vessel anastomosis: 9/0 or 10/0 nylon on a 3-6 mm needle with a tapered end; (2) nerve anastamosis: as above, but the needle has a cutting point; (3) fallopian tube work: 7/0 or 8/0 absorbable non-reactive suture with a 4 mm or 6 mm reverse cutting needle. • Sterilization: sterile rubber cups or drapes are available to cover the controls. • Adjustment: versatility in position demands several interlocking arms and counterbalanced vertical move- ment, as well as a geared angled coupling between the microscope carriage arm and body. This enables you to swing the microscope from side to side while mounted in an oblique axis. • Mounting: can be on a solid, well-balanced mobile floor stand, or a fixed ceiling mounting. Wall-mounted microscopes are also available. Control of tremor Counteracting surgical tremor is of vital importance. The instrument or the limb on which it is held must be firmly supported as close to the point of work as possible. The future The combination of the laser with a micromanipulator to the objective lens of the microscope will enhance the use of both instruments in the future. Summary • Are you familiar with the requirements of behaviour and technique to obviate operating room infection? • Have you learned the methods of positioning and moving unconscious patients to avoid injuring them? • Do you accept that you are in charge of the tourniquet, diathermy, laser, cryoprobe and X-rays in theatre? • Will you lead by example in the operating room, by adopting careful and responsible attitudes to delicate and potentially dangerous equipment? 197 17 PREPARATIONS FOR SURGERY ACKNOWLEDGEMENTS I am deeply grateful for help with writing this chapter to: Mr John Bancroft for the diathermy section; Dr David Parker for the section on X-rays in theatre; Mr Derry Coakley for the section on microscopes; and to my wife for her help in the section on lasers. I should also like to thank Miss Sharon Langford for typing the manuscript. I am grateful to Ethicon Endosurgery (a Johnson & Johnson Company) for information on the Harmonic Scalpel System; to the Microsulis Group for data on their Microwave Endometrial Ablation System; to Frigenis for help with the Autologous Transfusion Cell Salvage System; and to Valleylab for guidance on the use of the argon beam coagulator. Further reading Brigden RJ 1988 Operating theatre technique, 5th edn. Churchill Livingstone, Edinburgh Douglas DM (ed.) 1972 Surgical departments in hospitals: the surgeon's view. Butterworth, London Johnston IDA, Hunter AR (eds) 1984 The design and utilization of operating theatres. Edward Arnold, London Cell salvage Duguid JKM 1999 Review. Autologous blood transfusion. Clinical and Laboratory Haematology 21: 371-376 Diathermy Dobbie AK 1974 Accidental lesions in the operating theatre. NAT News December Earnshaw JJ, Keene TK 1989 Gastric explosion: a cautionary tale. BMJ 293: 93-94 Editorial 1979 Surgical diathermy is still not foolproof. BMJ 12: 755-758 Pearce JA 1986 Electrosurgery. Chapman & Hall, London Fibre optics MM, Swan CMJ 1984 Gastrointestinal endoscopy and related procedures - a handbook for nurses and assistants. Chapman & Hall, London Lasers 1982 General guidance on lasers in hospitals. Medical physics and bioengineering working group. Welsh Scientific Advisory Committee (WSAC) 1983 Guidance on the safe use of lasers in medical practice. HMSO, London Murray A, Mitchell DC, Wood RFM 1992 Lasers in surgery - a review. British Journal of Surgery 79: 21-26 Microscopes Taylor S 1977 Microscopy. Recent advances in surgery. Churchill Livingstone, Edinburgh, ch. 8 X-rays Ionizing radiation regulations 1985,1988 Mound RF 1985/1988 Radiation protection in hospitals (Medical Sciences Series). Adam Hilger, Bristol 198 18 Adjuncts to surgery A. L. G. Peel Objectives Recognize the importance of good theatre management. Ensure basic understanding of usage and care of theatre instruments, accessories and special equipment. Appreciate the place of implants and tissue glues in modern surgical practice. INTRODUCTION In health service economics an operating suite requires large capital and revenue budgets and this is favourably influenced by careful management of utilities. Good care of quality instruments ensures their long use; appropriate ordering and stocking means the shelf-life of equipment is not exceeded; wastage due to change in practice is reduced to a minimum; and storage space is efficiently used. The avoidance of an unnecessarily wide range of equipment and materials allows better use of capital. From the medicolegal aspect, the establishment of simple protocols aids efficient management within the theatre complex and helps to reduce errors, such as break- downs in sterility or retention of swabs or instruments in patients. A practical example of the rapidly changing scene in surgical practice is illustrated by orthopaedic surgery, where considerable expansion has occurred, particularly in prosthetic joint replacement, and in this field infection can result in very costly failure in terms of patient morbidity and financial implications to the health service. In the attempt to 'abolish' infection to elective orthopaedic surgery the following factors are considered important. Patient screening for occult infection Give particular attention to: • Possible urinary tract infection in females • Carrier status - postpone elective surgery until pathogens are eliminated, for example nasal Staphylococcus aureus. THEATRE MANAGEMENT 1. Orthopaedic theatre should be dedicated to 'clean' orthopaedics, where no dirty or contaminated orthopaedic operations and no general surgery is carried out. 2. Clean air enclosures. The routine use of clean air enclosures has reduced the infection rate in prosthetic joint surgery of hip and knee by more than half compared with conventionally ventilated theatres. Unidirectional air systems, especially with a downflow direction, reduces bacteria-carrying particles from 400-500 m- 3 to 30-40 m- 3 . Power tools produce additional problems because they create an aerosol spray, which effectively disseminates bacteria and viral particles. 3. Theatre gowns. Airborne bacterial dispersion can be further reduced by the use of appropriate fabric clothing. It is not widely appreciated that, in either conventional or unidirectional airflow theatres, the use of disposable fabric gowns alone in lieu of cotton gowns has not achieved a significant reduction in bacteria-carrying particles. Drawbacks to conventional clothing Bacteria from you, the surgeon, tend to be pumped by air through or out of cotton pyjamas and gowns into theatre air. Bacteria from you are drawn through wet clothing by capillary action, contaminating the sterile operative area. Contamination of you with patient's fluids. 199 [...]... with interferon alpha 2b New England Journal of Medicine 3 45: 1 45 2-1 457 Jeffries DJ 1995a Viral hazards to and from health care workers Journal of Hospital Infection 30(suppl.): 14 0-1 55 Jeffries DJ 1995b Surgery and bloodborne viruses PHLS Microbiology Digest 12: 15 0-1 54 Jeffries DJ 1997 Viral agents of bloodborne infections In: Collins CH, Kennedy DA (eds) Occupational bloodborne infections CAB International,... International, Wellingford, pp 1-1 6 Maffulli N, Capasso G, Testa V 1989 Glove perforation in elective orthopaedic surgery Acta Orthopaedica Scandinavica 60 :56 5- 5 66 222 Mast ST, Woolwine JD, Gerberding JL 1993 Efficacy of gloves in reducing blood volumes transferred during simulated needlestick injury Journal of Infectious Diseases 168: 158 9-1 59 2 Matta H, Thompson AM, Rainey JB 1988 Does wearing two pairs... such method is fibrin adhesion, based on the conversion of fibrinogen into fibrin on a tissue surface by the action of thrombin The fibrin is then crosslinked by factor XIIIa to create a firm stable fibrin network with good adhesive properties Fibrin foam may be valuable in controlling tumour bleeding The addition of aprotinin prevents premature dissolution of the fibrin clot by plasmin In the presence... (TSSU) and maintained by highly trained personnel Maintenance and performance tests are very strictly controlled In the future there will be a requirement for systems tracing the decontamination processes of surgical instruments Small portable autoclaves are used in some theatres for convenience There is a potential danger in that they are used by staff untrained in scrutinizing and maintaining them Many... guidelines for the control of methicillin-resistant Staphylococcus aureus infection in hospitals Report of a combined working party of the British Society for Antimicrobial Chemotherapy, the Hospital Infection Society and the Infection Control Nurses Association Journal of Hospital Infection 39: 25 3-2 90 214 Pratt RJ, Pellowe C, Loveday HP et al 2001 Standard principles for preventing hospital acquired infections... 23%, and in adults 5% or less become carriers This high rate of persistence following infection in early life largely explains the estimated 25 0-3 00 million carriers in the world, the majority of whom are in resource-deprived countries, where 1 5- 2 0% of the population may be infected The carrier of HBV presents a potential risk of horizontal transmission to others, predominantly via sexual intercourse... mucous membranes, including the eye, and high risk material (listed in Table 20.1) As in equivalent guidelines issued in the USA, the first-line drugs for postexposure prophylaxis are currently combined zidovudine (AZT) 300 mg and lamivudine (3TC) 150 mg b.d., and nelfinavir 1 250 mg b.d Treatment should start as soon as possible, ideally within 1 h of exposure, and should be continued for 1 month A... surgery Acetabuloplasty (cement-free prosthesis) Tendon repair Re-attaching osteochondral fragments Cardiovascular and thoracic surgery Prosthetic implant in combination with collagen sheet to seal lung air leaks Ophthalmic surgery Cataract operations ENT surgery Tympanic membrane surgery Sealing CSF leaks Urology Haemostasis, especially after TURP Plastic surgery Attaching skin grafts 18 anti-HIV-negative... materials in orthopaedic surgery 1 Surgical-grade stainless steel is used for joint replacement-bearing surfaces, plates, screws and wires 2 Alloys, including Vitallium, are also used in joint replacement surfaces, wires and, less frequently now owing to the preference for compression steel plating for internal fixation, in plates 3 High density polyethylene (ultrahigh molecular weight) is used for joint... for processing wrapped instruments or those with a narrow lumen In patients at risk of TSE, for procedures not involving high risk tissues, use the autoclave, after thorough cleaning of the instruments, with a cycle of 18 min at 134°C or six cycles of 3 min 2 Destroy instruments used for invasive procedures on patients known to have TSE, using incineration (ACDP 1998) The same applies to instruments . ligation of incom- petent perforating veins. Thin fibreoptic instruments are integral to the development of minimal access surgery, such as 5 mm telescopes used for retrieving bile duct stones. In . Medical staff clinically directing examinations employing ionizing radiation are required to have obtained a certificate demonstrating that they have received some training in radiation. Lasers in surgery - a review. British Journal of Surgery 79: 2 1-2 6 Microscopes Taylor S 1977 Microscopy. Recent advances in surgery. Churchill Livingstone, Edinburgh, ch. 8 X-rays Ionizing