Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 110 ppt

reported to be superior to a staged procedure. In a staged operation, the main decision must be made whether the condition of the patient will allow the opera- tion to be continued the next day. This offers the advantage that the monitoring devices like pulmonary artery or peripheral artery catheters can be left in place. Single stage surgery is generally advantageous but in elderly patients caution is warranted The main problems are coagulation disorders requiring a longer period of time between the two interventions. Complication rates, costs (hospital stay) and patients’ preference are in favor of single day interventions when compared to staged procedures. Pitfalls and Salvage Strategies Be prepared for typical pitfalls A knowledge of the typical pitfalls of an operation, and of strategies to cope with them, is necessary before starting. Pitfalls are either approach related or instru- mentation related. Instrumentation-related pitfalls often require special instru- mentsorimplants.Forexample,unexpectedpull-outofscrewsorhooksmay require special implants which should be available (e.g., thicker screw, bigger hook, or bone cement augmentation). Embolization Consider preoperative embolization for highly vascularized tumors Bleeding from a metastasis in the case of intralesional resection may be devastat- ing. Preoperative angiographic embolization should be considered, especially in renal carcinoma and thyroid cancer. Profound Knowledge of Anatomy This is as simple as it is obvious. Nevertheless, it should be stressed that a thor- ough knowledge of the anatomy and a clear vizualization of the surrounding structures are crucial if complications are to be avoided. Patient Positioning Blood Loss Prone position with a free abdomen reduces blood loss Excessive diffuse blood loss can be prevented in posterior procedures by ade- quate positioning (see Chapter 13 )ofthepatientproneonaReltonHallframe or other devices with a pendulous abdomen [70], which facilitates the draining of the epidural vessels. Excessive epidural bleeding can be minimized by: positioning of the patient with a hanging abdomen avoiding exploring the posterior surface of the vertebra (if not necessary) pushing aside epidural veins with the retractor before entering the disc space cauterization of veins which cannot be kept away [68] Postoperative Blindness Check the headrest to avoid pressure on the eyes There are numerous case reports of spinal surgeries which ended with unilateral or bilateral visual loss [3, 65, 81, 112]. The main cause is retinal artery occlusion due to pressure on the eye globe by the headrest, ischemic optic neuropathy, and cerebral ischemia. Most cases underwent posterior instrumentation with a long operation time [81]. All precautions to avoid ocular compression must be taken. 1094 Section Complications Neuromonitoring Define your workflow on perioperative changes of evoked potentials Paraplegia cannot be fully avoided, but any preventive measure with some likeli- hood of reducing the incidence must be undertaken, including: intraoperative spinal cord monitoring [24, 108] thorough control of fluid volume, blood loss, and blood pressure If evoked potentials show increasing potential latency or decreasing amplitude, immediate reaction is required. Somatosensory evoked potentials (SSEPs) usu- ally have a delay in the response, so that a clear association with a certain opera- Motor evoked potentials are more sensitive tive step may not be obvious. Motor evoked potentials (MEPs) are more sensitive [90] so that reaction by either reducing correction or by removing a screw or a hookcanbedone.Inthecaseofanydoubt,awake-up test is necessary. If the wake-up test indicates a neurological deficit, implant removal is required. There are no good comparative studies on the effect of implant removal after pathologi- cal potentials and a pathological wake-up test have taken place. In view of the In cases with iatrogenic neurologic deficit, complete implant removal is counter- productive if a floating spine will result lack of clear evidence in the literature, implant removal is recommended, and also in the light of medicolegal issues. In some specific cases, however, there are clear arguments for leaving the implants inplace, for example in the case of resec- tion of vertebra where implant removal will cause the situation to deteriorate. Approach-Related Complications Thereissomeoverlapinprocedureandapproachrelatedcomplications.Ingen- eral, the anterior approach ( Table 5) is more prone to serious complications than Table 5. Incidence of complications in anterior thoracolumbar surgery Category Complication Rate Sample size Intervention Author Anterior lumbar interbody fusion mortality 0.15% 684 mini-open anterior lumbar Brau (2002) [15] 1.0% 207 anterior thoracolumbar Oskouian (2002) [88] direct vascular injuries 3.4% 207 anterior thoracolumbar Oskouian (2002) [88] arterial injuries 0.8% 684 mini-open anterior lumbar Brau (2002) [15] 0.08% 1223 anterior fusion Faciszewski (1995) [33] venous injuries 0.8% 684 mini-open anterior lumbar Brau (2002) [15] deep venous thrombosis 2.4% 207 anterior thoracolumbar Oskouian (2002) 1.0% 684 mini-open anterior lumbar Brau (2002) [15] 0.3% 318 “major” Dearborn (1999) [23] pulmonary embolism 2.2% 318 “major” Dearborn (1999) [23] retrograde ejaculation 0.1% 684 mini-open anterior lumbar Brau (2002) [15] 1.7% 116 male retroperitoneal Sasso (2003) [99] 8% 50 male retroperitoneal Christensen (1997) 13.3% 30 male transperitoneal Sasso (2003) [99] 17.5% 40 male transabdominal Tiusanen (1995) ileus >3 days 0.6% 684 mini-open anterior lumbar Brau (2002) [15] superficial infection 1.0% 1223 anterior fusion Faciszewski (1995) [33] deep infection 0.6% 1223 anterior fusion Faciszewski (1995) [33] Anterior spinal deformity surgery pulmonary complications 4.9% (2.2%) 447 miscellaneous, deformities McDonnell [77] related to chest tube 1.8% (2.7%) 447 miscellaneous, deformities McDonnell [77] gastroenterological 1.1% (2.9%) 447 miscellaneous, deformities McDonnell [77] related to wound 1.1% (2.7%) 447 miscellaneous, deformities McDonnell [77] hematological 0.9% (0.2%) 447 miscellaneous, deformities McDonnell [77] operative 0.7% (1.1%) 447 miscellaneous, deformities McDonnell [77] neurological 0.7% (1.8%) 447 miscellaneous, deformities McDonnell [77] genitourinary 0.4% (11.6%) 447 miscellaneous, deformities McDonnell [77] cardiac 0.4% (0.9%) 447 miscellaneous, deformities McDonnell [77] death 0.4% 447 miscellaneous, deformities McDonnell [77] Note: When two rates are quoted, the first refers to major, and the second (in brackets) to minor, complications Treatment of Postoperative Complications Chapter 39 1095 the posterior one, and some occur more often in the lumbar spine, others in the cervical spine. For the purpose of this chapter, the complications are described where they occur most frequently. Anteromedial Cervical Approach Vessel Lacerations Arterial lacerations and venous lacerations are rare, and the same treatment methods as mentioned in the chapter on lumbar vessel laceration can be applied. The internal jugular vein may be ligated unilaterally. Thrombosis of the internal jugular vein frequently occurs associated with hemodialysis catheters, and with- out important sequelae [116]. Vertebral artery injury occurs in 0.3–0.5% of ante- romedial interventions, especially in: complete corpectomy with resection of the lateral vertebral wall injuries by a burr lateral placement of an instrument excessive lateral disc removal intraoperative loss of the midline landmarks An anomalous medial course of the artery is described and was found in an ana- tomic study in 2.7% of patients. Therefore, preoperative imaging is mandatory [61]. Superior Laryngeal Nerve Lesion Thesuperiorlaryngealnerve(SLN)originatesfromthemiddleofthenodose ganglion of the vagus nerve and divides after an average of 15 mm into an inter- nal and external branch. Caution is extremely important if the contralateral side was operated on for thyroid surgery or neck surgery,orwasirradiated.Abilat- eral lesion interrupts the afferent part of the cough reflex and can cause life- threatening aspiration [78]. The external branch (ESLN) courses distally poste- rior to the superior thyroid artery, and innervates the cricothyroid muscle, which is responsible for regulating the tension of the vocal cords by rotating the cricoid cartilage. A lesion causes slight hoarseness, voice fatigue, loss of high tonalities, and decrease in voice volume. Therefore, prudence is particularly indicated in singers, teachers and professional speakers. Treatment is not possible. Caution is necessary in any cervical spine operation rostral to C4 [60]. Recurrent Laryngeal Nerve Lesion Check larynx function in case of previous surgery or radiation In a study of 328 cases of anterior cervical spine surgeries, incidence of a lesion was 2.7%, and lesions occurred with the same rate in right and left sided approaches [10]. The main symptom of a unilateral lesion is hoarseness. A bilat- eral lesion can cause severe problems to breath, but is assumed to be extremely rare in cervical spine surgery. Continuous laryngeal nerve integrity monitoring did not decrease recurrent laryngeal nerve (RLN) complications in non-random- ized controlled studies regarding thyroidectomy. Many false negative cases occurred during monitoring [97, 121]. Spontaneous recovery occurs in about one-third of cases. In the case of previous surgery on the contralateral side, in neurological disorders or after irradiation, preoperative laryngoscopy is neces- sary to avoid a bilateral lesion. 1096 Section Complications Hypoglossal Nerve Lesion The hypoglossal nerve can be damaged in anterior approaches to the upper cer- vical spine, and C1/C2 Magerl screws ( Case Study 1) penetrating the anterior cor- tex of the atlas. A lesion causes tongue deviation to the ipsilateral side. Treatment is not possible but spontaneous recovery is frequent. ab cd Case Study 1 A 79-year-old female presented with severe neck pain 5 months after a fall. The radiologic assessment (a) revealed a dense non-union. Non-operative measures failed and surgery was indicated based on a very painful atlantoaxial instabil- ity. A posterior atlantoaxial screw fixation was done with a 5-cm incision at the C1/2 level and a percutaneous screw insertion under biplanar image intensifier control. The skin entry points for the transarticular screws were at the level of T2/3 and the screw trajectory could not be angled more steeply because of the upper thoracic kyphosis with compensa- tory cervical hyperlordosis. The screw placement and Gallie fusion with a titanium cerclage were carried out uneventfully ( b, c). The patient recovered from the surgery without any obvious neurological deficit. However, on the second postop- erative day, a deviation of the tongue was noticed. A thorough neurological examination was otherwise unremarkable. An MRI scan was done to rule out any central lesion or bleeding. The T2-weighted MRI scan ( d) demonstrated a perfora- tion of the anterior cortex which was done intentionally to increase screw purchase in an osteopenic bone. However, the screw had irritated the hypoglosseus nerve which runs in front of the axis. The tongue deviation recovered spontane- ously. This case indicates that the anterior cortex should not be perforated with transarticular screws. Treatment of Postoperative Complications Chapter 39 1097 Anterior Approach to the Cervicothoracic Junction Lesions to the RLN and Horner’s syndrome are described in some case reports. Lesions of large vessels can occur and care must be taken that the surgery can cope with this potentially life-threatening complication [13]. The availability of a vascular surgeon should be clarified preoperatively. Thoracotomy Lung Lacerations A laceration of the lung can be created during blunt dissection of pleural adhe- sions or by direct trauma with an instrument. Air will exit and can be made visi- ble by irrigation fluid. Treatment includes local closure of the leak and a chest Suturing the lung is not easy because the suture tends to cut out tube. The pleura can be sutured using a 4/0 continuous suture, or synthetic mate- rial ( Table 6). Fibrin sealant can be injected afterwards to make the lesion air- tight. In order to avoid sutures cutting through the lung tissue, the suture has to be placed with a perpendicular, grasping a larger piece of lung tissue to avoid cut- ting out. Table 6. Synthetic hemostatic materials Name Company Material Indications Extended indications FloSeal Baxter bovine derived gelatine and thrombin with mixing acces- sories and syringe when control of bleeding by liga- ture is ineffective epidural bleeding, lung lacera- tion TachoSil Nycomed collagen sponge coated with human fibrinogen and throm- bin for supportive treatment of hemo- stasis where standard techniques are insufficient pleural defects Gelfoam Pfizer water-insoluble porous prod- uct from purified pork skin gelatine. Hemostatic mecha- nism not fully understood as a hemostatic device, when other procedures are either ineffective or impractical Avitene Davol Inc., Cranston, RI, USA a microfibrillar collagen product apply pressure with a dry sponge. theperiodoftimemayrangefrom a minute for capillary bleeding to 3– 5 min for brisk bleeding or arte- rial leaks in neurosurgery apply with a moist sponge. For control of oozing from bone, it should be firmly packed into the spongy bone surface Note: Extended indications are not quoted here! The product description of the company has been shortened. For full details see the company description! Use two chest tubes in case of a hematopneumothorax In the case of broad pleura adhesions, a large area of the pleura can be destroyed. This area can be covered with Tachosil ( Table 6). Air exiting from alveoli will not cause a problem. It can be drained by the chest tube, and the lung will heal. Air exiting from bronchi requires closure of the leak. This is beyond the scope of an orthopedic surgeon, and a thoracic surgeon must be involved. In any case, a chest tubehastobeplacedwheretheairisexpectedtoaccumulate,usuallyanteriorto the lungs, if the patient is lying in the supine position. Lacerations of the Thoracic Vessels Do not try to repair pulmonary artery lesions – compress them until help arrives! The azygos or the hemiazygos veins are most likely to be injured, and can be ligated, as well as the segmental vessels. The risk of anterior spinal artery syn- drome increases with bilateral ligation of segmental arteries. If this is planned, clamping and neuromonitoring is required. The aorta can be sutured as 1098 Section Complications described below. A lesion of a pulmonary artery requires the most experienced thoracic/vascular surgeon available. Pneumothorax Atrocarguidedchesttube insertion is dangerous If air in the thorax is detected postoperatively, a chest tube is placed with local anesthesia. A trocar guided chest tube insertion is regarded as dangerous. We prefer a direct tube insertion after mini-thoracotomy (3–4 cm incision). In the supine position, the drain must be beneath the anterior chest wall. Tension pneu- mothorax may occur, if not drained. Findings are respiratory distress, tachypnea, unilaterally decreased or absent respiration, tachycardia, and hypotension as the key signs of tension pneumothorax. Hematothorax Place the chest tube anteriorly to drain air and posteriorly to drain blood If bleeding is expected, a chest tube has to be placed where blood is likely to accu- mulate, usually lateral to the spine and posterior in a patient lying in the supine position. The chest tube will be removed after criteria established by the depart- ment. Some surgeons remove the tube after 24 h, others, if less than 200 ml per day is collected. There is no evidence in the literature on the best way. If more than 600 ml blood per hour is lost, revision thoracotomy must be considered. If hematothorax occurs after chest tube removal, ultrasound guided puncture may be sufficient for minor bleedings. Chylothorax Postoperative chylothorax is treated by parenteral nutrition and chest tube Thechyleinthethoracicductisamilky fluid.Inanteriorapproachestothetho- racic spine, especially in trauma or deformities, the thoracic duct may be injured. Ligation is possible, but the vessel is usually hard to find. Therefore, it is better to cover the area, where the leak is suspected, with synthetic material, e.g., Tachosil ( Table 6). A chest tube has to be placed posteriorly. The loss of chyle may be con- siderable and can range up to 6 L/day (average production is 40 ml/kg body weight). Treatment is normally non-surgical with either total parenteral nutri- tion or enteral low fat solid food or an enteral elemental diet supplemented with intravenous lipid emulsion, until the lymph leak heals, which takes an average of 30 days. Lymphocytopenia and hyponatremia are frequently seen [84]. Pleural Abscess The stage of the disease decides the required procedure. In early cases with liquid pus, chest tube drainage is sufficient. Failure to evacuate the pleural space or per- sistent signs of infection should prompt surgical intervention by open thoracot- omy or thoracoscopic evacuation. In late cases with lung entrapment, decortica- tion (resection of the visceral pleura) may be necessary. Insufficient Postoperative Oxygenation Insufficient postoperative respiration can occur in patients with deformities and severely impaired lung function, and in neuromuscular diseases such as A thoraco-phrenico- lumbotomy decreases vital capacity by about 20% Duchenne’s disease. An approach through the diaphragm (Hodgson approach) causes a reduction of vital capacity of about 20% for one year. A rib hump resec- tion may cause a decreased lung volume [71]. Both measures can cause a border- line sufficient respiration to deteriorate. On the other hand, if correction does not reduce lung volume, corrections can be performed even in patients with a vital Treatment of Postoperative Complications Chapter 39 1099 capacity of less than 40%. Recently, Wazeka et al. reported on deformity correc- tion in 21 patients with a mean predicted vital capacity of 32%, who needed post- operative supplemental oxygen for 0–90 days. Two developed pneumonia, two pleural effusions, and atelectasis was found four times. There were no mortalities or adverse neurological outcomes [115]. Tracheotomy may be required if the patient is not able to breath sufficiently for days. Exercises can increase the vital capacity as well. In rare cases with no recovery, there is a need for a continuous oxygen supply via a transportable oxygen bottle. Thoracolumbar Approach The same lesions as with the thoracic and lumbar anterior approaches can occur but the liver and the spleen are at risk during this approach. Liver Lesion Repair of a bleeding liver lesion requires a specialized surgeon A subcapsular hematoma does not require an intervention. Open bleeding from the liver requires a specialized surgeon. Postoperative suspicions should be investigated with ultrasonography. Splenic Injury There are few case reports of accidental splenic injury during anterior spine approaches [20] especially the left sided approach to L1/L2. In other interven- tions like esophagectomy, the mortality and sepsis rate increase with splenec- tomy. Therefore, preservation of the spleen should be the aim of treatment when- ever a splenic injury occurs. Observation or hemostatic agents can be used for grade 1 and 2 (subcapsular hematoma <50% of surface) [79]. Reconstruction or resection is the treatment of choice in grades 3 (>50%) to 5 (shattered spleen). Anterior Lumbar and Lumbosacral Approach Due to the high rate of anterior lumbar interventions and the proximity of ves- sels, the lumbar spine is the most common location of vessel lacerations. Arterial Laceration After suturing an artery, check for thrombosis and monitor vascularization by pulse oximetry An intraoperative open arterial bleeding is usually caused by sharp dissection of the artery. This can occur accidentally with a sharp instrument, or during dissec- tion in scar tissue. A temporary vessel loop may facilitate the repair ( Fig. 1 ). How- ever, the inexperienced surgeon is at risk of increasing the problem when trying to prepare for the insertion of the vessel loop. It is recommended that the less experi- enced surgeon is better to wait for the help of a vascular surgeon. A simple incision of the artery can be sutured with 3-0 monofilament double ended sutures for the aorta and 4-0 for thicker vessels like the common iliac artery ( Fig. 2 ). It is impor- tant to suture the entire wall of the artery including the intima; otherwise the intima can occlude the vessel ( Fig. 3 ). Occlusion of the vessel adjacent to the lacera- tion by vessel loops is mandatory. Thrombectomy with a Fogarty catheter has to be done first, and intravascular heparin (5000 IU) is administered before final clo- sure. Just before the last knot is made, some blood is allowed to escape, in order to get the air out of the vessel. Tomake the suture tight, synthetic hemostatic material ( Table 6 ) may be administered. Due to the risk of postoperative arterial thrombo- sis, it is recommended to consult a vascular surgeon in any case. Postoperative monitoring of the blood circulation of the leg is required using a pulse oximeter. 1100 Section Complications Figure 1. Vessel loop A vessel loop is put twice around the artery. With this technique the artery can be closed by pulling on both ends. abc Figure 2. Suture of a tear in a vessel A monofilament double ended atraumatic suture is used. One end of the suture is fixed, and then a continuous suture is made with the first needle, and consecutively with the second needle. In small children, single knots are better, because a continuous unresorbable suture cannot grow. This suture technique can also be used to repair a dural leak. ab Figure 3. Suture of a tear in an artery The suture canal should be oblique. The intima is perforated further away from the tear than the serosa, in order to create eversion of the vessel wall, and to avoid the intima occluding the vessel. Treatment of Postoperative Complications Chapter 39 1101 Arterial Thrombosis Avoid pressure on lumbar arteries by sharp-edged retractors or pins The rate of arterial thrombosis was 0.45% in 1315 consecutive cases undergo- inganteriorlumbarsurgeryatvariouslevelsfromL2toS1[16].Themain causes are either a tear in the intima, or compression of more than 50% of the lumen. Atherosclerotic plaques increase the risk. A cautious surgical technique can reduce the incidence of arterial thrombosis. The pressure of sharp-edged retractors or of pins should be avoided [66] and artery and veins should not be separated in order to keep the lymph vessels and crossing blood vessels intact. Even in posterior fusion, direct pressure on the inguinal region may cause occlusion [1]. Do not postpone treatment by planning angiography or ultrasound Late symptoms are paralysis and sensory impairment usually of the left leg, and cyanosis of the toes. Delayed thrombectomy after wound closure and angi- ography will cause severe residual symptoms due to compartment syndrome [19, 47, 66, 74, 94]. Therefore, arterial thrombosis must be detected before symp- toms occur. Similarly to arterial laceration, postoperative monitoring with a pulse oximeter is essential. V enous Laceration Major vein lacerations are usually detected during surgery. If a vein is com- pressed, a stab wound can be caused by a pin. In anterior lumbar interbody fusion, the left ascending iliolumbar vein is recommended to be ligated in advance, because avulsion may be difficult to treat. There are several opportuni- ties for treatment: Suture Usually, a 5-0 double ended monofilament suture is used (Fig. 2). Direct repair is chosen if the defect is easily accessible, and if the resulting stenosis is expected to be less than 50% of the lumen. Some stenosis can be accepted, and may be even beneficial, causing a higher speed of blood flow which may reduce thrombosis rate. Postoperatively, heparin treatment for 5–7 days or during hospital stay is recommended followed by LMWH or other vitamin K antagonist treatment for 4–6 weeks, in order to prevent rethrombosis. Heparin treatment can be per- formed for example with enoxaparin (Lovenox) starting 4 h after surgery (1 mg/ kg two times per day). Postoperative monitoring for thrombosis is also essential. The recurrent thrombosis rate is 20%. Doppler sonography studies are recom- mended in the case of clinical suspicion. Compression and Hemostatic Agent Most small venous lesions are sealed by pressure only The maintenance of pressure for about 5 min is essential, and is usually per- formed with the help of a collagen sponge. Hemostatic agents ( Table 6)arecho- sen either if the tear size is less than 5 mm or if the tear is difficult to access. Ligation Ligation is the method of choice in catastrophic situations. Before ligation of a large vessel, a vascular surgeon should be consulted. Other measures including end-to-endanastomosisaswellasinterpositiongraftsorpatchesmustbecon- sidered. The common iliac vein can be ligated in a life-threatening situation. Even the inferior vena cava can be ligated below the renal veins, and sequelae like permanent edema of the legs are rare [111]. 1102 Section Complications The mortality from major abdominal vessel injuries is high In a recent study [86], 18% of patients with iatrogenic injuries to major abdomi- nal or pelvic veins died due to: uncontrollable bleeding multisystem organ failure pulmonary embolism The blood loss ranged from 500 ml to 20000 ml. Therefore, any attempt must be undertaken to avoid venous lacerations. Bowel Perforations These are rare and usually occur during anterior procedures. There are also some case reports of perforations during microdiscectomy [42, 55, 58]. A laceration of Bowel perforations must be repaired the serosa can be sutured superficially. A perforation will require continuous two- layer stitches, through the periphery of the mucosa and the entire muscle. If a part of the bowel is destroyed, resection will be necessary. The likelihood of contamina- tion and consequently of the formation of abscesses increases from proximal to distal, with almost no danger of contamination in the small intestine, and a high danger in the sigmoid colon. Postoperative antibiotic treatment is required. Ureteral Injury Some cases were reported which occurred during anterior lumbar surgery, espe- cially in laparoscopic surgery [44] and disc prosthesis [39]. The diagnosis is often made postoperatively, and the main reasons are misplaced stitches or clips to stop bleeding. Treatment is an end-to-end anastomosis or implantation of the rest of the ureter into the urinary bladder performed by a urologist. A short-lasting contu- sion by a stitch or a hemostat usually does not require surgical treatment, but requires postoperative observation including ultrasonography of the kidney [49]. Urinary Bladder Injury The incidence is rare. The urinary bladder is sutured with two sutures. After suturing the muscularis and mucosa with continuous atraumatic 3-0 stitches, the peritoneum is separately sutured. A urethra or suprapubic catheter is applied for 10 days, and antibiotics are administered during this time [49]. Posterior Approach to the Cervical Spine Postoperative Kyphosis Postoperative kyphosis results can result from inappropriate technique Failed reattachment of the semispinalis during laminoplasty may lead to postop- erative kyphosis. Reattachment should be performed, but anatomic variation has to be considered [110]. Resection of the C2 spinous process should be avoided in order to prevent kyphosis. Vertebral Artery Injury The lesion is rare and occurs in 4.1% of transarticular (C1/2) screw fixations [120]. Biplanar imaging guidance has decreased the incidence. Most patients remain asymptomatic after the incidence. The risk of neurological deficit from vertebral artery injury was 0.2% per patient or 0.1% per screw, and the mortality rate was 0.1% [120]. Devastating complications may occur in lesions of a unilat- eralartery,orinthecaseofacontralateralarterywiththinlumen.Preoperative Treatment of Postoperative Complications Chapter 39 1103 . periphery of the mucosa and the entire muscle. If a part of the bowel is destroyed, resection will be necessary. The likelihood of contamina- tion and consequently of the formation of abscesses. is the treatment of choice in grades 3 (>50%) to 5 (shattered spleen). Anterior Lumbar and Lumbosacral Approach Due to the high rate of anterior lumbar interventions and the proximity of ves- sels,. study of 328 cases of anterior cervical spine surgeries, incidence of a lesion was 2.7%, and lesions occurred with the same rate in right and left sided approaches [10]. The main symptom of a