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Ankylosing Spondylitis Chapter 38 1085
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Trang 4Treatment of Postoperative Complications
Martin Krismer, Norbert Boos
Core Messages
✔ The best treatment for complications is their
avoidance by careful preoperative planning
✔ Neurological complications are no more
fre-quent in spinal than in musculoskeletal surgery
✔ Check risk factors for complications such as
intraspinal pathology, previous surgery,
aller-gies, medications and malnutrition
✔ Use standardized postoperative protocols to
monitor the patient with regard to neurological
and cardiopulmonary function as well as
vascu-lar status (pulse oximetry)
✔ Try to stop bleeding from small lacerations of
large veins by pressure and hemostatic agents
✔ Cover lacerations of the lungs with synthetic
material
✔ Chylothorax is initially treated by parenteral
nutrition
✔ Hypoliquorrhea syndrome usually occurs with
tiny dural defects and not with large lacerations
Frequency of Complications
The rate of complications with spinal procedures is dependent on the type of
sur-gery, the spinal pathology, the experience of the surgeon and confounding factors
such as age and comorbidities These factors have to be taken into account in the
discussion of complications.
Cervical Spine Surgery
Postoperative deterioration must be anticipated in cases
of preexisting myelopathy
In 450 cases of anterior cervical discectomy, worsening of the preexisting
cervi-cal myelopathy occurred in 3.3 % and infection in 1.6 % Additional
radiculopa-thy occurred in 1.6 %, recurrent nerve palsy in 1.3 %, and Horner’s syndrome in
1.1 % An epidural hematoma was seen in 0.9 % Furthermore, single cases of
pharyngeal lesion, meningitis due to a dural leak, and an epidural abscess were
found [9] In decompression for ossification of the posterior longitudinal
liga-ment the neurological complication rate was 3.6 % [85] In anterior fusion in 488
patients, a dural tear occurred in 0.2 %, dysphagia in 1.4 %, a fractured vertebra
in 0.2 %, and vocal paresis in 0.8 % [48] In a report on 185 corpectomies, the
ver-tebral artery was injured in four patients [31].
Trang 5a b
Case Introduction
A 38-year-old male underwent lumbar discectomy at the level of L5/S1 for a left-sided radiculopathy with a sensory and motor (MRC Grade IV) deficit of the S1 nerve root The microsurgical procedure was completed uneventfully The patient reported immediately after surgery a substantial pain relief and improvement of the muscle force for plantar flexion of the left foot At discharge, the patient felt well and was almost pain free At 2 weeks postoperatively the patient consulted his family practitioner because of intermittent headache The patient was treated symptomatically with NSAIDs The symptoms increased and the patient again developed some minor leg pain for which he was referred again On presen-tation, the patient complained of position-dependent headache which got worse after 15 – 20 min in the upright posi-tion An MRI scan demonstrated a fluid collection at the level of surgery (a, b, d) A contrast-enhanced MR scan allowed the exclusion of a recurrent herniation (d) A hypoliquorrhea syndrome was suspected and the patient was reviewed Intraoperatively, a medium size (5 cm) arachnoidal cyst was discovered which was opened At the base of the cyst, a tiny dura lesion was discovered under the lamina of S1 It was assumed that the lesion only injured the dura but left the arach-noidea intact This injury was obviously unnoticed intraoperatively because no CSF leak occurred The cyst was resected The dura lesion was sutured with 5-0 Prolene and covered with Dura-Gen and fibrin clue The patient completely recov-ered and was symptom free at 2 months follow-up This case demonstrates that a hypoliquorrhea syndrome is most often observed not with large but with a tiny dura lesion which forms a valve mechanism We recommend repairing all iatrogenic arachnoidal cysts when noticed intraoperatively to avoid this complication
Trang 6Anterior Spine Surgery
Serious complications are rare
In anterior approaches to the adult thoracic or lumbar spine, serious
complica-tions are relatively rare In two large studies (n = 1 223 [33], n = 447 [77]), the
major complications were:
) death: 0.3 %, 0.4 %
) paraplegia: 0.2 %, 0.4 %
) deep wound infection: 0.6 %, 1.1 %
In a report on 205 disc prostheses enrolled in a prospective FDA study [11], the
major complications were:
) death: 0.5 % (anesthesia related)
) neurological deficit: 0 %
) deep wound infection: 0 % (superficial 6.3 %)
The overall complication rate for idiopathic scoliosis was 5.2 % for anterior, 5.1 %
for posterior, and 10.2% for combined anterior and posterior procedures
according to a study by the Scoliosis Research Society [21] based on 6 334 cases
submitted to the study in the years 2001, 2002, and 2003 ( Table 1 ).
Table 1 Complications in adolescent idiopathic scoliosis surgery [21]
In a French deformity surgery cohort, 90 % scoliosis, 10 % kyphosis (n = 3 311),
the overall complication rate was 21.3 % Infection occurred in 4.7 % and
neuro-logical complications in 1.8 % [43].
Disc Herniation and Spinal Stenosis
Several papers reported on complications in surgery for disc herniation [62], or
posterior procedures, where decompression of disc herniation or of spinal
steno-sis contributed to 84 % of the cases, and where fractures, infections and
malig-nant lesions were excluded [26] In 27 576 and 18 122 operations death occurred
in 0.5 % (within 30 days) and 0.07 %, respectively Mortality depended strongly
Perioperative mortality depends on age and comorbidities
on age, being 0 % up to the age of 40 years, and 0.6 % at the age of 75 years and
over [26] Most deaths occur in elderly patients due to:
) cardiac infarction
) heart failure
) central nervous system complications
) septic shock
The incidence of an iatrogenic neurological deficit was cited as 1.0 % for disc
her-niation and 1.8 % for stenosis [85] A dural leak occurred in 1.4 % The incidence
of a leak decreased with increasing surgical experience from 3.1 % (experience
1 – 6 years) to 1.1 % (> 15 years), whereas the surgeon’s experience did not
influ-ence the rate of neurological complications.
Treatment of Postoperative Complications Chapter 39 1089
Trang 7Lumbar Spinal Fusion
The overall early complication rate in a prospective randomized trial [38] on 211 patients was 6 % in posterolateral fusion without instrumentation, 18 % with posterior instrumentation, and 31 % in circumferential fusion The complica-tions consisted of:
) infection rate: 3.6 % (5 of 140 posterior fusions) ) injury to the sympathetic trunk: 3.7 %
) injury to iliac veins: 3.7 % ) new nerve root pain: 7.1 %
Comparison of Complications
Complications are no more
frequent than in other
musculoskeletal surgery
Spine surgery is no more prone to complications than other major orthopedic interventions Lethal and even neurological complications occur more often in hip, knee and shoulder arthroplasty than in spine surgery ( Table 2 ).
Table 2 Complications in musculoskeletal surgery
lesions
Infection References
Schmalzried et al (1991) [102]
Schnisky et al (2001) [101]
Schmalzried et al (1991) [102]
) surgery for anterior glenohumeral instability – 1 – 8 % – Boardman et al (1999) [12]
Herrera et al (2002) [54]
) shoulder arthroplasty 0.2 – 0.6 % 1 – 4 % 1.1 % Boardman et al (1999) [12]
Farmer et al (2006) [35] Sperling et al (2001) [106]
Preventive Measures
Better avoid than treat
complications
It is self-evident that it is better to avoid complications than to treat them Com-plications cannot be avoided completely, but the best conditions can be created to
obtain a low complication rate This goal is achieved by:
) preoperative identification of risk factors ) patient referral to a larger center (in case of insufficient surgical experience) ) optimal patient preparation (e.g., correction of malnutrition)
) standardization of procedures ) postoperative checks to detect neurological, pulmonary, and cardiovascular deterioration
It is quite obvious that an experienced specialist will cause fewer complications But to be clear, experience is what we get when complications occur which we have to manage The experienced surgeon and much more so the surgeon’s patients have to pay a price for this experience The opportunity to gain experi-ence must be weighed against the risk This should be kept in mind when rare cases are selected for surgery.
Trang 8Screening of Risk Factors
A screening investigation of major risk factors ( Table 3 ) is recommended in
order to identify the population at risk The screening should encompass a full
medical examination.
Table 3 Risk factors for complications
) excessive blood loss ) neuromuscular deformities (hypotonia, osteoporosis)
) neurofibromatosis (abnormal vascular anatomy)
) drugs (platelet inhibitors, anticoagulants)
) scar formations (previous surgery)
) arteriosclerosis (smoking)
) thromboembolic complications ) previous thromboembolic episodes
) malignant tumor
) congenital deformity
) preoperative neurological deficit
) spinal cord compression
) general complications ) malnutrition
) previous cardiac infarction or stroke
) neuromuscular diseases
Risk Factors for Vascular Complications
A detailed preoperative search for risk factors for vascular complications can
help to minimize the surgical risk The preoperative assessment should consider:
) previous surgery (e.g., of vessels, thorax, abdomen, spine, thyroid gland)
) history of coronary heart disease, high blood pressure, diabetes mellitus,
transient ischemic attacks, thromboembolism [41, 98]
) claudication symptoms [2]
) clinical examination of pulses (leg, foot, carotid arteries)
Routine radiographs of the spine may show extensive arteriosclerosis which may
caution one to perform mobilization and retraction of vessels It is debatable
whether Doppler sonography is routinely necessary but it is indispensable if the
patient reports a previous history of transient ischemic attacks or a murmur.
Some situations should definitely be avoided, e.g., a bleeding vertebral artery
with no information on the function of the contralateral artery, or the presence of
an abdominal scar without knowledge of the type of the previous surgery (e.g.,
vascular prosthesis) It is not clear whether information on the circle of Willis is
routinely necessary, which would require angiography (MR or conventional) in
cervical spine cases However, in the case of a stenotic vertebral artery this may
be important information.
Cardiovascular Risk Factors
Cardiac complications are mainly myocardial infarction and heart failure.
Stroke is a rare complication Most case reports of strokes in spinal surgery are
related to iatrogenic vertebral artery injury In a few, carotid occlusion occurred.
After previous myocardial infarction and after stroke, elective procedures
should not be done within a period of 6 months if not imperative For endoscopic
Elective surgery after a myocardial infarction should
be postponed for 6 months
procedures it was shown that complications from an intervention in the first
30 days were no higher than in those patients operated on 6 months after
myocar-dial infarction [18] No information is available with regard to major orthopedic
procedures.
Treatment of Postoperative Complications Chapter 39 1091
Trang 9Pulmonary Risk Factors
Inability to climb more than
two floors increases the risk
of pulmonary complications
Risk factors are chronic obstructive pulmonary disease (COPD), often caused by
smoking, and restrictive lung disease especially in deformities The ability to climb stairs may be a good indicator, e.g., the ability to climb three floors without interruption indicates a sufficiently good lung function In COPD, it is important for the patient to sit upright postoperatively Especially in muscular dystrophy (Duchenne’s disease), respiratory muscle training may increase preoperative vital capacity Nevertheless, the surgical intervention should not be delayed, and
it was recently shown that the outcome is no different in patients with a vital capacity e 30% in comparison to those with vital capacity >30% [50].
Malnutrition as Risk Factor
Malnutrition is a frequently underestimated risk factor It is therefore necessary
to routinely assess the nutritional status well in advance of elective major
sur-gery The assessment of nutritional parameters should include:
) albumin ) prealbumin ) total protein ) transferrin ) absolute lymphocyte count
It was shown in prospective randomized trials [59, 69] that parenteral nutrition after surgery can reduce postoperative infections such as pneumonia or urinary tract infections Malnutrition is frequently present in:
Malnutrition is a frequently
underestimated risk factor
) elderly people ) patients with neuromuscular diseases ) patients with malignant tumors ) staged operations [27]
A preoperative high protein diet may therefore be beneficial [69].
Medication
Aspirin should be stopped
10 days prior to surgery
Platelet aggregation inhibitors such as acetylsalicylate and clopidogrel can
con-siderably increase bleeding They should be stopped 10 days before the planned intervention, or they should be replaced directly by low molecular weight heparin
(LMWH) Non-steroid anti-inflammatory drugs (NSAIDs) may increase the
effect of anticoagulants If high doses of NSAIDs are taken, a preoperative change
to paracetamol (in the absence of liver disease), tramadol or other opioids should
be considered, in order to reduce the bleeding risk Hormone replacement ther-apy in menopause and oral contraceptives both increase the risk of venous throm-bosis Metformin in therapy of diabetic patients may be related to a higher periop-erative risk of lactic acidosis Therapy should be changed 48 h prior to surgery.
Intraspinal and Nerve Root Pathology
Nerve root anomalies
are not uncommon
Conjoined nerve roots (two nerve roots in one foramen), and connecting roots may require decompression by foraminectomy or resection of a pedicle In a recent study, the rate of conjoined nerve roots was found to be 5 % [104] Coronal magnetic resonance imaging (MRI) is the best method to detect these abnormali-ties Intraspinal malformations and tethered cord are not a risk per se However,
an intraspinal abnormality seen on MRI in combination with either an abnormal
Trang 10neurological examination and/or abnormal evoked potentials at preoperative
baseline spinal cord monitoring indicates a spinal cord at risk [72] The most
important pathological findings indicating unsuspected neurological disorders
are asymmetric abdominal reflexes.
Always search for absent abdominal reflexes
The prevalence of tethered cord in a Turkish study on 5 499 schoolchildren
was 0.1 % in all children, and 1.4 % in enuretic children [4] In juvenile scoliosis
[29] and in cases of hemivertebrae [6], more than 20 % of patients showed spinal
cord abnormalities on MRI such as Arnold-Chiari malformation, syringomyelia,
diastematomyelia, or a low conus Enuresis, gait disturbances, dermatologic
signs of dysraphism, spina bifida on plain X-rays, and congenital deformities are
frequently associated with tethered cord and cord malformations MRI is
recom-mended in these cases, and also in left thoracic idiopathic scoliosis.
Preoperative Planning
The operative strategy has to be clearly defined before the intervention, and is
based on imaging Surprising findings concerning the extent of a tumor,
joined nerve roots, or vessels entrapped in a scar can be ruled out or can be
con-firmed in advance Especially in deformities the direction of pedicle screws can
be determined in advance with the help of a CT scan, if navigation is not
avail-able The fusion level must be determined in advance In this context, the
land-marks to determine the correct fusion levels should be assessed, e.g.:
Anatomic structures are not reliable enough to determine the correct level
) Are there only 11 ribs?
) Is the C6 transverse process also prominent?
) Are there 6 lumbar vertebrae?
Especial caution is necessary if the indication is based only on MRI findings in
the upper lumbar or thoracic spine, such as endplate (Modic) changes, which
cannot be seen in the image intensifier Perioperative measures ( Table 4 ) are
helpful to prevent complications.
Table 4 Perioperative measures to prevent complications
Cervical anterior
Thoracic anterior
Lumbar anterior
Posterior Deformity
surgery
Note: ✔ in any case; ~ in selected cases
Timing of Surgery
A same day anterior and posterior procedure saves time and the nutrition status
is better However, the longer the operation, the more tired the surgeon and the
higher the blood loss A staged procedure may have advantages in the case of:
) myelopathy [114]
) anticipated excessive blood loss (coagulation disorders)
) very long surgeries (exceeding the patient’s or surgeon’s tolerance)
Otherwise, simultaneous surgery (two surgeons operating on two approaches at
the same time) [25] or same day anterior and posterior [119] procedures are
Treatment of Postoperative Complications Chapter 39 1093