weight patients are at higher risk [22, 105]. Causal treatment is reduction of the correction.Thisisusuallynotrequired.Thesymptomswillamelioratewithin weeks and with intravenous hyperalimentation. In rare cases, duodenojejuno- stomy will be required. Urogenital Complications Urinary Tract Infection Check for bladder residual urine The most frequent urogenital complication is a simple urinary tract infection (UTI), which can occur in up to 9% of patients [5]. Ascending infection with pyelonephritis or sepsis is rare. These complications can be minimized when perioperative catheterization is used only when absolutely indicated. On the other hand, incomplete bladder emptying also increases the risk of infection. Ultrasonography is very helpful in estimating the residual urine amount, which should be less than 100 cc. Postoperative Anuresis Check perianal sensation in postoperative anuresis In the immediate postoperative period, patients often have difficulty in urinat- ing. The most frequent cause is the inability to empty the bladder in a lying posi- tion. However, anal tone and sensation must be controlled to rule out a cauda equina syndrome. Early mobilization solves this problem. If this is not possible, catheterization is necessary to avoid bladder overdistension. Urinary Bladder Dysfunction Afteranteriorsurgery,abladderdysfunctioncanresultfromaninjurytothe parasympathetic presacral nerves especially at the level of L5/S1. This complica- tion can perhaps be reduced by a retroperitoneal approach, where the sympa- thetic and parasympathetic fibers located close to the peritoneum in the bifurca- tion of the vessels are left intact [34]. Retrograde Ejaculation Initial reports have perhaps underestimated the problem. A survey of 20 sur- geons in 1984 reported 0.42 % retrograde ejaculation and 0.44% impotence fol- lowing anterior lumbar spine fusion [37]. The more thoroughly studies were undertaken, the higher (2–4%) was the reported incidence [8, 11, 99]. It seems that the problem is mainly approach related, with the incidence being much higher in transperitoneal than in retroperitoneal approaches to the lumbar spine. This complication is most likely more common than reported Recently,inanteriorlumbarinterbodyfusiontheratewas2%inretroperitoneal and 13% in transperitoneal cases [99]. A lesion of the hypogastric plexus must be avoided during approaches to the lumbar spine. The plexus is located in front of the vessel bifurcation, close to the peritoneum. In transperitoneal approaches, the plexus is split directly under the peritoneum. Retroperitoneal approaches allow for preparation behind the vessels, so the plexus can be preserved. The restrictive use of bipolar cauterization may reduce the risk. 1114 Section Complications Recapitulation Frequency of complications. Complication rates of spinal procedures are dependent on the type of surgery, spinal pathology, the experience of the sur- geon and confounding factors such as age and co- morbidities. The most frequent complications of cervical surgery are infection (1.6%) and Horner’s syndrome (1.1%) as well as neurologic deteriora- tion (3.3 %) in cervical myelopathy. In anterior spinal surgery, death and paraplegia are encountered in 0.3–0.4% and 0.2–0.4%, respectively. The overall complication rate for posterolateral fusion is about 6% and is dependent on the age of the patient. Im- plant related neurological compromise and post- operative wound infection are among the most frequent complications. Preventive measures. The best treatment for com- plications is their avoidance. Important measures to prevent complications are the screening for risk fac- tors such as past history of thromboembolic com- plications, previous postsurgical infections, previ- ous surgery, malnutrition, cardiovascular disease, COPD, smoking, and medications (e.g., NSAIDs). Detailed preoperative planning including potential salvage strategies is mandatory to minimize the risk of complications. A profound knowledge of the sur- gical anatomy is indispensable. Correct patient po- sitioning reduces blood loss. Neuromonitoring is a must in cases in which deformity correction is at- tempted. Approach-related complications. The superior and recurrent laryngeal nerve and the cervical ar- teries are at risk when performing an anteromedial cervical approach. Lung lacerations and injuries to the thoracic vessels may occur when a thoracotomy is done. Pulmonary artery lesions are very chal- lenging to repair even for very experienced thoracic surgeons. Postoperative pneumothorax and he- matothorax can be avoided by proper drainage. A chylothorax can become a life-threatening prob- lem and requires temporary parenteral nutrition. A thoraco-lumbar approach may jeopardize the liver and spleen. Venous and arterial injuries may occur with abdominal approaches and require adequate repair and aftertreatment. Bowel and urethral inju- ries arerarebutmustnotbeoverlooked. Procedure-related complications. Excessive epi- dural bleeding is a frequently encountered prob- lem during posterior decompressive surgery and can be reduced with correct patient positioning. Nerve root injuries subsequent to posterior Instru- mentation can be minimized with proper training and experience. Unintended durotomy is not infre- quent in cases with severe spinal canal stenosis, and direct repair is recommended whenever pos- sible. Distraction during deformity correction is prone to neurological compromise and must be avoided. Hypotensive surgery should be avoided when correcting severe spinal deformity. Reduc- tion of high-grade spondylolisthesis jeopardizes the L5 nerve root and complete reduction should therefore be avoided. Postoperative complications. Postoperative moni- toring must include blood loss, neurological and vascular status. Continuous postoperative bleed- ing is a frequent problem particularly after posteri- or revision surgery and spinal osteotomies. This problem can be minimized with proper intraopera- tive hemostasis and timely blood and factor substi- tution. Persistent wound drainage is indicative of infection or malnutrition. A hypoliquorrhea syn- drome only occurs with tiny leaks not discovered intraoperatively and which most often need to be repaired. Postoperative vascular complications are rare but may be detrimental if overlooked, particu- larly large vessel injuries with continuous bleeding or arterial thrombosis. Pulmonary complications can be minimized with proper preoperative respira- tory treatment. The duration of postoperative bowel atonia can be reduced by avoiding extensive opioid treatment and alternatively using postoper- ative peridural anesthesia. Urinary tract infections are not infrequent and routine catherization for short surgeries should be avoided. The rate of retro- grade ejaculation (2–13%) is more frequent than as- sumed and can be reduced by avoidance of cauter- ization of the pre-discal vessels. Treatment of Postoperative Complications Chapter 39 1115 Key Articles BaronEM,AlbertTJ(2006) Medical complications of surgical treatment of adult spinal deformity and how to avoid them. Spine 31:S106 – 18 Recent extensive review of complications in adult spinal surgery. Bungard TJ, Kale-Pradhan PB (1999)Prokineticagentsforthetreatmentofpostopera- tive ileus in adults: a review of the literature. Pharmacotherapy 19:416 – 423 A good description of how to treat postoperative bowel atonia. The different pharmaceu- tical options are discussed. Coe JD, Arlet V, Donaldson W, Berven S, Hanson DS, Mudiyam R, Perra JH, Shaffrey CI (2006) Complications in spinal fusion for adolescent idiopathic scoliosis in the new mil- lennium. A report of the Scoliosis Research Society Morbidity and Mortality Commit- tee. Spine 31:345 – 9 Review of complications in 6334 patients undergoing surgery for adolescent idiopathic scoliosis. FlinnWR,SandagerGP,SilvaMBJr,BenjaminME,CerulloLJ,TaylorM(1996)Prospec- tive surveillance for perioperative venous thrombosis. Experience in 2 643 patients. Arch Surg 131:472 – 480 An excellent study of all aspects of thrombosis and pulmonary embolism in spine sur- gery. The article demonstrates the relatively low risk of venous thrombosis in comparison to orthopedic procedures like arthroplasty of large joints. Faciszewski T, Winter RB, Lonstein JE, Denis F, Johnson L (1995) The surgical and medi- cal complications of anterior spinal fusion surgery in the thoracic and lumbar spine in adults. A review of 1 223 procedures. Spine 20:1592 – 1599 This article is a good overview of the incidence of complications of anterior deformity surgery. The overall estimation of the risk is perhaps too optimistic. Therefore the article by Leung and Grevitt (2005) cited below is recommended in addition to achieve a more balanced view. Fritzell P, Hagg O, Nordwall A; Swedish Lumbar Spine Study Group (2003)Complica- tions in lumbar fusion surgery for chronic low back pain: comparison of three surgical techniques used in a prospective randomized study. A report from the Swedish Lumbar Spine Study Group. Eur Spine J 12:178 – 189 An overview of all aspects of complications in lumbar fusion, showing a high increase of complications with instrumentation and further with 360° fusion. In the further course, several articles were published by the same authors, showing fewer complications like pseudoarthrosis in the midterm with instrumented 360° fusion. Inamasu J, Guiot BH (2005) Iatrogenic vertebral artery injury. Acta Neurol Scand 112:349 – 357 This article describes all iatrogenic causes of vertebral artery lesions, including percuta- neous puncture, treatment options and outcome. Jansson KA, Nemeth G, Granath F, Blomqvist P (2004)Surgeryforherniationofalum- bar disc in Sweden between 1987 and 1999.Ananalysisof27 576 operations. J Bone Joint Surg Br 86:841– 847 This is the best casuistry on complications of surgery for disc herniation. A remarkable mortality of 0.5% was found in the first 30 days after surgery, which was clearly associ- ated with increased age. KraemerR,WildA,HaakH,HerdmannJ,KrauspeR,KraemerJ(2003) Classification and management of early complications in open lumbar microdiscectomy. Eur Spine J 12:239 – 246 This review article gives a good overview of complications after lumbar microdiscectomy, with recommendations on treatment. Lapp MA, B ridwell KH, Lenke LG, Baldus C, Blanke K, Iffrig TM (2001)Prospectiveran- domization of parenteral hyperalimentation for long fusions with spinal deformity: its effect on complications and recovery from postoperative malnutrition. Spine 26:809 – 817 This paper emphasizes the importance of sufficient alimentation in avoiding periopera- tive spinal complications. 1116 Section Complications Key Articles LeungYL,GrevittM,HendersonL,SmithJ(2005) Cord monitoring changes and seg- mental vessel ligation in the “at risk” cord during anterior spinal deformity surgery. Spine 30:1870 – 1874 A valuable article for identification of patients at risk of paraplegia. Timberlake GA, Kerstein MD (1995) Venous injury: to repair or ligate, the dilemma revisited. 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Surgery 136:1107–15 Treatment of Postoperative Complications Chapter 39 1121 40 Outcome Assessment in Spinal Surgery Mathias Haefeli, Norbert Boos Core Messages ✔ The evaluation of treatment modalities for spi- nal disorders by self-administered question- naires has entered into clinical practice ✔ Functional and psychosocial aspects often exhibit a closer correlation with fair or poor outcome after spinal surgery than organ-spe- cific symptoms and morphological alterations and must therefore be evaluated in outcome research ✔ The main subjects addressed by outcome tools are pain, disability, health-related quality of life and work status ✔ For more thorough investigations, psychosocial aspects, work-related parameters and fear avoidance behavior should additionally be assessed ✔ There are several standardized and validated questionnaires available ✔ Current research is trying to facilitate data assessment by developing short but reliable instruments General Concepts of Outcome Assessment The evaluation of treatment modalities in spinal orders by self-administered assessment tools has become standard in most institutions. In many fields of medicine and particularly in spinal surgery, it has become evident that treatment outcome is influenced by a large variety of non-morphological factors [100]. Psy- chosocialaspectsandwork-relatedfactorsoftenexhibitahigherpredictivevalue than pathomorphological and surgical aspects [47]. Therefore, it has become apparent that a meaningful outcome assessment should consider most of these confounding variables, which, however, is not always possible to achieve in a busy clinical practice. The minimal data set that should be collected consists of: pain disability quality of life work status Several criteria should be considered when data assessment is performed by self- rating questionnair es: comparability validity availability scale characteristics When a comparison between treatment groups is chosen in a study, the criteria ofcomparabilityofaquestionnairemustbedefined.Iftheresultsaretobecom- Outcome Assessment Section 1123 pared with a control group out of the literature, an identical questionnaire must be used. Validity[2]isthedegreetowhichaninstrumentmeasureswhatitisintended to measure. It is the most important quality of a questionnaire and there are dif- ferent types of validity. A questionnaire ideal ly should fulfill: content validity, i.e. the extent to which the instruments include the domain of the target phenomenon criterion validity,i.e.extentofagreementwhencomparingwitha“gold standard” construct validity, i.e. extent to which the instrument corresponds to theo- retical concepts of the target phenomenon Most of the questionnaires are developed for the English language. If these tools are used in non-English speaking countries, these versions should ideally be translated and validated first for the used language (availability). Several rules should be considered in this process of cross-cultural adaptation [13]. According to this, such a process should start with at least two forward translations into the target language. In a second step a synthesis of the two translations should be done before performing at least two back translations in the next step. After a consolidation of all versions of the instruments resulting from the first three Table 1. Outcome tools in spinal surgery Topic Tool Available languages (validated versions only) Pain VAS/GRS/NRS/VRS Disability RMDQ English [131] French [38] German [156] Greek [24] Portuguese [115] Spanish [88] Swedish [82] Turkish [90] ODI English [50] Finnish [63] French [157] German [11, 101, 102] Greek [24] NASS-Q English [39] German [123] Italian [119] FAQH German [86] NDI English [145] French [157] Swedish [3] NPDI English [154] French [157] Turkish [20] Quality of life WHOQOL-100/-Bref www.who.int SF-36/-12/-8 www.sf36.com EQ-5D www.euroqol.org SRS-22/-30 English: www.srs.org Spanish [10] Fear avoidance behavior FABQ English [149] German [121, 138] Core item tools Low back pain English [41] German [99] Neck pain English [155] 1124 Section Outcome Assessment . of the pre-discal vessels. Treatment of Postoperative Complications Chapter 39 1115 Key Articles BaronEM,AlbertTJ(2006) Medical complications of surgical treatment of adult spinal deformity and. evaluation of treatment modalities in spinal orders by self-administered assessment tools has become standard in most institutions. In many fields of medicine and particularly in spinal surgery,. and review of the literature. J Neurosurg 90:35–41 32. Epstein NE (2005) A review of the risks and benefits of differing prophylaxis regimens for the treatment of deep venous thrombosis and pulmonary