Lumber Anterior Midline Approach
What is a lumber anterior midline approach?
This surgical technique is most frequently used for anterior lumbar surgery. In other words, the lumbar spine region is approached through a midline vertical or horizontal skin incision made on the anterior aspect (front). Although most spinal surgeries are performed using a posterior (back) approach, a surgeon may choose an anterior method for a number of reasons, including: gaining direct access to the damaged intervertebral disc or avoiding multiple surgeries in one area if the patient has already undergone previous procedures using a posterior approach, among others.
The patient lies on his back and his skin is cleaned. A midline abdominal incision is made over the involved region between the ribs to the pelvis, and the underlying central fascia is cut and moved to the sides. Typically the spine is approached without disrupting the pouch containing the intestines (peritoneal cavity).
Adhesions – Abdominal
The formation of scar tissue is a natural part of the body’s healing process and typically doesn’t cause any problems. Adhesions, however, are abnormal bands of scar tissue that can forms over months, even years. As the name suggests, abdominal adhesions may occur after adnominal surgery and can become attached to the abdominal wall and internal organs, causing pain. These bands of scar tissue can block the intestines and cause obstruction and may need to be surgically removed.
Artery Injury – Common Iliac
The common iliac artery is a paired structure, which means that there is one on the right and one on the left side of the body. Located in the lower abdomen, it supplies blood to the pelvis and leg. Injury to the artery is uncommon and its generally very obvious if it is has been damaged, which means it can be repaired immediately if necessary. This can, however, be a dangerous complication, resulting in loss of large blood volumes and loss of blood supply to the lower limb.
Arteries are large blood vessels that carry blood under pressure throughout the body. Surgeons take extreme care not to injure arteries near the operation site as a perforation can lead to significant blood loss. In the unlikely event that an artery is perforated, a specialist vascular surgeon will repair the artery, and a blood transfusion is administered. Late consequences of artery injury include fistula, haemorrhage, pseudoaneurysm, thrombosis, emboli and death.
Arteries are large blood vessels that carry blood from the heart to the rest of the body and the heart muscle. Arterial thrombosis is a blood clot in an artery, which can be very serious as it can stop blood reaching important organs. During surgery, it is sometimes necessary for arteries to be moved to the side or compressed to allow access to the operation site. This pressure can lead to a clot forming within the artery (this is more likely in older patients with pre-existing blood vessel disease). A large clot can block the artery, while a small clot can dislodge and become an embolus, which travels and eventually blocks a small artery. Blocked arteries lead to insufficient blood flow or ischemia in the tissues supplied by the artery. This can cause damage to these tissues, which may be permanent, depending on the duration of the blockage. Ischemia in the legs can cause pain and gangrene, if it occurs in the brain it can cause a stroke and in the spinal cord, it can cause paralysis and altered sensation.
No operation is risk-free. Complications resulting from a procedure can range from minor troubles to major disability. Even when a surgery has gone well, serious problems can still arise and result in pneumonia, heart attack, stroke or even death. The entire medical team is highly trained and committed to eliminating all risk pre-, during and post-surgery as much as is humanly possible.
Given that the intestines lie adjacent to the surgical site they must be moved to gain access to the spine. This means that there is a risk that the intestines may be perforated. While these perforations are difficult to detect they can be repaired, but should they go undetected, serious infection, fever, bloating and pain may occur. An unseen perforation may need another operation to clean and seal the perforation.
During any surgery, some blood vessels will be cut. And although the surgeon stops all significant bleeding before closing the wound, there are instances in which bleeding restarts and forms a collection of blood in the tissues. Known as a hematoma, this can cause pain, put pressure on the adjacent tissues or become infected. A drainage tube may need to be inserted or a surgical operation performed.
Surgeons may need to cut some blood vessels in order to access the spinal operation site. The surgeon will plan the surgical route to avoid large blood vessels and will make sure that all bleeding has stopped before finishing the operation. Occasionally, one of these vessels can re-bleed after the procedure and if the rate, or the location of the bleed is problematic, a further procedure may be needed to stem the bleeding and drain the accumulated blood clot.
Hernia – Incisional
A hernia is a condition in which part of an organ is displaced and protrudes through the wall of the cavity containing it. An incisional hernia is when a hernia occurs at the site of a former surgical wound. They commonly occur in the abdominal wall, can form at any time and are often a result of excess tension applied to the wound before it has healed, or a wound that has been weakened due to infection, poor nutrition, diabetes, obesity or a prior disease. Hernias can cause pain and form a lump consisting of fatty tissue or an internal organ. More often than not, they become larger and more painful and need to be surgically repaired.
Post-operative ileus is a temporary paralysis of the bowel. This condition is usually caused by narcotic pain-killing medications, intra-abdominal, spine or chest surgery. Symptoms include abdominal discomfort and bloating, constipation, nausea or vomiting. Through fasting and minimizing the use of narcotic medication, most cases will settle within three days. Occasionally though the stomach may need to be emptied using nasogastric suction tubes and intravenous feeding and fluid is required.
Infections occur in less than 1% of spinal operations and are more likely in patients that smoke, have diabetes, are overweight, or had a hematoma. Symptoms of an infected wound include: increased pain, swelling, tenderness, redness, oozing (clear or yellow fluid), slowness to heal, or if the patient experiences fever or chills.
Infections can be superficial (involving the skin), which usually respond to oral antibiotics and washing of the site. Sometimes the wound needs cleaning and re-suturing. Deep infections (involving the vertebrae or spinal cord) are more serious and may need intravenous antibiotics and an operation to drain the infection. On rare occasions, infected bone graft or hardware may need to be removed.
This rare life-threatening condition is passed down through families and can be triggered by some drugs that are used for general anaesthesia. In susceptible people, the drugs can cause an uncontrolled increase in skeletal muscle calcium levels and muscle contraction, leading to decreased blood oxygen and increased blood carbon dioxide and body temperature. This can lead to circulatory collapse and death if not quickly treated. Symptoms usually develop within an hour of drug administration. As yet, there is no simple test to diagnose susceptibility but it is usually found during drug administration or suspected if a family member develops the symptoms. While treatment is effective, it is critical that patients, who have a family history of malignant hyperthermia, discuss this with their doctor so that the use of the potential trigger drugs can be avoided.
Nerve injury – Lumbar
Vertebrae surround the spinal nerve roots. This means that accessing or repairing damaged vertebra can potentially bruise, stretch, tear or cut these nerves roots – either within the spinal canal – or as they leave the spinal canal through the invertebral foramen. Locating, protecting and mobilising the spinal nerves can be the most sensitive and time-consuming part of spinal surgeries. If a nerve is damaged, the injury can cause temporary or permanent pain or bladder and bowel dysfunction as well as partial or complete loss of sensation or movement in the patient’s leg.
Nerve injury – Lumbar Sympathetic Plexus
The lumbar sympathetic nerves lie near the lumbar spine. Any injury to these nerves during surgery can result in pain and increased blood supply to the relevant leg. Although the effected leg appears redder, drier and warmer, most people describe this sensation as coldness of the opposite leg. These symptoms usually settle over time.
Nerve injury – Ulnar
During surgery the medical team carefully positions the patient’s body so that the injured region is easily accessible. This can result in the ulnar nerve (located in the arm) being compressed or stretched at the elbow. Symptoms of pain, numbness or weakness in the hand can appear up to 4 days after surgery and usually disappear over a few weeks.
The spine surrounds and protects the spinal cord. This means that any surgery to the spine carries a degree of risk and the surgeon takes great care when working on the operation site. Damage to the thoracic, lunar or sacral spinal cord can cause loss of movement and sensation in the lower half of the body. It can be complete, with no movement or sensation below the level of the spinal cord injury, or incomplete with some movement or sensation. Paraplegic patients generally need to use wheelchairs or other walking aids. Urinary and faecal incontinence and impotence are common and paraplegics are at an increased risk of pressure sores, thrombosis and pneumonia.
The spinal cord, nerves, dura, arteries and veins are important structures that lie close to the operation site. Although the surgeon takes extreme care when operating, these structures can be accidentally perforated during the procedure. This risk also applies to the intestine in the abdomen, the lungs in the chest and the oesophagus and trachea in the neck.
The peritoneum is a thin membrane that lines the inside of the abdominal wall. It can be torn during abdominal surgery but tears are repaired during surgery. Any tears that are missed can lead to bowel adhesions or intestinal herniations.
Prolonged surgery and bed rest can result in the formation of skin pressure sores over prominent bones. The nursing team carefully place, pad and manoeuvre the patient to prevent this from happening.
During male ejaculation the sphincter muscle at the outlet of the bladder contracts and stops semen from entering the bladder, forcing it down the urethra. If however, the sphincter muscle is weak or the nerves that control it are damaged during spinal surgery, semen can enter the bladder. While retrograde ejaculation is not dangerous it can decrease sensation during orgasm and decrease fertility.
The ureters, which drain urine from the kidneys to the bladder, are located near the lumbar spine. If any injury to the ureters occurs during spinal surgery it can be repaired immediately. Unseen injuries can cause blood in the urine, abdominal pain, distention, ileus and infection. These symptoms may recover spontaneously or need further surgery.