Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 111 potx

Reports on cauda equina syndrome caused by postoperative continued epidural bleeding are rare [52].. It may be caused by several mechanisms: distraction hypotensive anesthesia vessel

imaging is mandatory in order to determine salvage strategies in advance.

Hemostasis may be achieved by compression and packing If the lesion occurred

during drilling, a screw in the drill hole is a good option The screw at the oppo-site side, if not in place, should be skipped, and a salvage Gallie procedure can be performed instead of using Magerl screws Pseudoaneurysm and arteriovenous fistulae are rare sequelae [61] Stenting may be efficacious

Posterior Approaches to the Thoracic and Lumbar Spine

Approach-related intraoperative complications are rare Excessive bleeding can occur The risk is reduced by adequate patient positioning and change of platelet inhibitors and anticoagulants to other drugs preoperatively Very rarely, lesions

of anterior structures occur due to direct accidental stab trauma Relatively rare

is an accidental lesion of the dural sac or of the spinal cord during preparation of the approach It is mandatory to use imaging to determine whether the posterior vertebral elements are intact; otherwise, preparation has to be conducted with more caution

Procedure Related Complications Decompressive Cervical and Lumbar Surgery

Check preoperative X-rays

for bony defects

Decompressive surgery in the cervical and lumbar spine is the most frequently performed intervention but also prompts the need for revisions and surgery of the adjacent segments In some cases, complications can be avoided if the preop-erative radiograph is checked for bony defects In primary cases, this precaution helps to avoid unintended dural lacerations (e.g., in spina bifida occulta)

Epidural Vein Bleeding

The blood loss may be considerable and can substantially reduce visualization, compromising surgical success Epidural bleeding usually stops after wound clo-sure and turning the patient into the supine position Reports on cauda equina syndrome caused by postoperative continued epidural bleeding are rare [52] Severe bleeding from epidural veins occurs in 3.5 % in the hands of very experi-enced surgeons, and in 7 % in the hands of experiexperi-enced surgeons [68]

Wash out Floseal after

epidural vein bleeding

has stopped

If severe bleeding occurs, it is sometimes better to continue removing the disc herniation rather than attempting to coagulate the bleeding epidural vessels Bleed-ing often stops after removal of the disc herniation and facilitates exploration of the bleeding vein Compression of the vessel with a neurosponge allows the bleeding to

be controlled in the vast majority of cases Generally, bipolar cauterization may be necessary but should be limited because of postoperative scarring Floseal is a very efficient material to stop epidural bleeding Usually, this agent increases its volume,

so that application in the vertebral canal requires caution Removal of the agent by irrigation is recommended when the bleeding has stopped

Nerve Root Injuries

A nerve root may be damaged by:

) malpositioning of a pedicle screw (Fig 4) ) direct pressure or traction during decompression (e.g., PLIF procedures) ) sharp instrumentation (high speed burrs)

) cauterization (heat)

a b

Figure 4 Malpositioning of a lumbar pedicle

which has led to a nerve root irritation The pedicle was still intact after screw hole preparation with a blunt pedicle finder

(4 mm) However, the pedicle screw (7 mm) perforated the pedicle cortex, which was not noticed In questionable cases,

it is recommended to again remove the screw after it has passed the pedicle and entered the vertebral body However,

do not completely insert the screw if you want to remove it again to probe the pedicle because of the limited bony

pur-chase with screw reinsertion.

Poor visualization due to bleeding, perineural fibrosis, or congenital vertebral

(e.g., dysplastic pedicle) or neural abnormalities (conjoined nerve roots)

increases the risk of damage The most vulnerable area for a lesion is the axilla of

the nerve root Therefore, a good preventive principle is to stay lateral to the

nerve root when removing disc material [68] Herniating root fibers have to be

reduced, and the defect has to be closed However, a suture of the dura is very

dif-ficult and can cause stenosis A fat or collagen pad or an artificial dura (e.g.,

Tis-sueDura) with fibrin sealant is recommended to close the leak

Cauda Equina Syndrome

There are several reports on postoperative cauda equina syndrome after

discec-tomy for lumbar disc herniation [28, 52] A frequent cause is extraction of a large

disc fragment through a small flavum window (microsurgical approach) The

syndrome is caused by direct pressure or by postoperative hematoma A further

cause may be venous congestion in the presence of preexisting lumbar spinal

ste-nosis [52] Extended decompression as soon as possible is recommended but

recovery is often only partial

Unintended Durotomy

The risk of unintended durotomy and cerebrospinal fluid (CSF) leaks can be

reduced with increasing surgical experience However, sometimes minor tears

may become symptomatic only days or weeks after surgery (Case Introduction)

Dural tears should be repaired (if possible)

In severe spinal stenosis, which often presents with adhesions, dural tears occur

even in the hands of experienced surgeons Closure of the defect is generally

rec-ommended The following treatment options are available:

The leak should be covered with a neurosponge until the repair is performed The leak can be sutured with non-resorbable 5-0 suture (interrupted or running) and should be watertight But care must be taken not to create a stenosis or suture in

a root fiber It is debatable whether a small arachnoidal cyst should be opened prior to the repair In this setting, Gehri et al [40] have reported a case in which the suture of an arachnoidal cyst injured a small dural vessel and created a sub-dural hematoma It is advisable to control the tightness of the sub-dural repair before closing the wound This is done either by tilting the table to increase the pressure

within the dura, or by high pressure respiration (increased PEEP) The muscle

fascia of the back muscles and the skin should be sutured so they are watertight

Patch

If the dura is extremely thin or a large defect was created, the defect can be cov-ered with fascia, muscle, fat, or synthetic material such as Tissue-Dura (Baxter), Durepair (Medronic) or DuraGen (Integra) A fibrin sealant (e.g., Tissucol) can

be used to improve the closure In complicated cases, however, a formal plastic repair is necessary In complicated cases, an external CSF drainage is necessary

Leave It Open

Small CSF leaks often cause

more problems than large

defects

If there is no way to close the leak, it can be left open In this case, it is absolutely necessary to avoid formation of a CSF fistula, i.e., the wound closure must be watertight A pseudo-meningocele sometimes develops but usually does not harm the patient The CSF is very pervasive and will find its way out of the body

A drainage (as overflow) is therefore recommended until the skin has healed Repair the dural defect

whenever possible

Antibiotic prophylaxis is recommended as long as there is drainage from the wound or a drain is in-situ In cases with adequate dural repair, bedrest is usually not required NSAIDs are administered for headache

Lesions of Anterior Structures

Some case reports exist of intra-abdominal vascular or bowel injuries during lumbar disc surgery [42, 44, 113] Frequently, the stab wound is caused by a sharp instrument or a rongeur (perforating the anterior anulus fibrosus) When using

a sharp instrument (e.g., chisel), the instrument has to be held tight to counteract forces exerted by the hammer The surgeon must always be aware that a structure can suddenly break or is released jeopardizing underlying structures

Anterior vessel injury by a

posterior approach is a

life-threatening complication

In the devastating situation of a major bleeding from an anterior vessel, the

patient has to be turned supine after compressing the wound with sponges as effectively as possible The posterior wound should be closed provisionally with large stitches The patient should immediately be positioned supine for an ante-rior approach Vessel repair must be done by the most experienced (vascular) surgeon available

Deformity Correction

Spinal Cord Injury

Spinal cord injury is the most serious complication and most frequently occurs in deformity correction There may be several reasons for spinal cord injury:

Direct Spinal Cord Injury

Direct spinal cord injury can occur by implants, instruments or bony spurs

Direct injury may occur by improper placement of screws, hooks, sublaminar

wires, or may result from a fracture of the lamina, pedicle or posterior wall of the

vertebral body during correction maneuvers Postoperative MRI may reveal

bleeding or ischemia in the spinal cord Even delayed spinal cord injury can

occur due to compression by an implant in a narrow spinal canal [64] For legal

reasons, the proportion of paraplegia caused by direct injury is not known

How-ever, reports on neuromonitoring, where evoked potentials were restored after

implant removal, suggest that these cases exist

Distraction

Distraction leading to spinal cord injury is an avoidable complication

Distraction may cause paraplegia especially in rigid angular curves, and in the

presence of malformations like diastematomyelia, where distraction of the spinal

cord can move the cord along a bony or fibrous spur in the cord In more than half

of the cases of diastematomyelia combined with congenital scoliosis, a

neurologi-cal deficit can be found preoperatively [56]

Anterior Spinal Artery Syndrome

Anterior spinal artery syndrome is a devastating complication Somatosensory

evoked potentials are likely to be false negative at the onset of the syndrome [7,

83], but motor evoked potentials will show the lesion immediately It may be

caused by several mechanisms:

) distraction

) hypotensive anesthesia

) vessel ligation

) unknown causes

Avoid spinal deformity correction in severe hypotensive and hypovolemic anesthesia

The blood flow in the anterior spinal artery can be decreased during distraction

At least 65 % of baseline blood flow is required to maintain spinal cord integrity

[83] Hypotensive anesthesia or a sudden decrease of blood pressure may

inter-rupt sufficient oxygen supply of the motor fibers In this condition, deformity

correction should be avoided until blood pressure and volume have been

cor-rected

Vessel ligation can cause anterior spinal artery syndrome in vascular surgery

for aortic aneurysm However, it is very unlikely to cause paraplegia in

orthope-dic cases, because in deformity surgery it is done unilaterally and on the

convex-ity of the curve Nevertheless, it is recommended to provisionally clamp vessels

(control the effect with MEPs), ligate vessels only at the midvertebral level

(collat-eral supply), and to avoid hypotensive anesthesia

Avoid low postoperative hemoglobin and hypotension after large deformity correction

In a large study, not a single case of paraplegia was found in more than 1 000

anterior operations [118] In tumor resection, bilateral artery ligation may be

required, and there are some reports of the syndrome in these cases [30]

Para-plegia especially due to anterior spinal artery syndrome can occur up to 3 days

after surgery [107] In cases with large deformity corrections, low postoperative

hemoglobin and hypotension should be avoided to allow for an adequate

vascu-larization of the spinal cord, which may be compromised by the correction [51]

Reduction of High-Grade Spondylolisthesis

Neural Injuries

In high-grade spondylolisthesis (see Chapter 27), particularly the L5 nerve root

is at risk The incidence depends on the surgical technique and may be higher than 50 % if full reduction is attempted [14] More than 50 % of the lesions resolve with time The nerve root lesion can become clinically apparent even hours after

the completion of the operation Neural compromise can occur by three

mecha-nisms:

) cauda equina compression ) foraminal impingement ) nerve root stretching Avoid complete correction

of high-grade

spondylolis-thesis

A cauda equina syndrome can occur as a result of a compression over the

poste-rior edge of the sacral dome after in situ arthrodesis with or without

decompres-sion [75] Immediate decompresdecompres-sion including resection of the dorsoapical rim

of the sacral dome is recommended [103] Foraminal stenosis is a frequent

find-ing in high-grade spondylolisthesis [63] Correction of the lumbosacral kyphosis reduces the foramen even more Sagittal translation of the slipped vertebra

causes a non-linear nerve root stretch (70 % of the stretch occurs after a

reduc-tion of more than 50 %) [91] It is therefore recommended to avoid a correcreduc-tion

of more than 50 %

Major Bleeding

Complete corpectomy

in high-grade

spondylo-listhesis may lead

to life-threatening uncontrollable bleeding

In Gaines procedures (complete corpectomy of the slipped vertebra), life-threat-ening bleeding can occur from the pre-sacral venous plexus Sponges and

hemo-static agents (Table 6) can be used to control bleeding

Corpectomy/Osteotomy

Excessive Bleeding from Bone

Blood loss during corpectomy and osteotomy can be excessive and can rapidly cause hemodynamic problems Control of bleeding by compression with sponges

is the first method which creates time for further planning If the bleeding is from cancellous bone, bone wax and hemostatic agents are helpful (Table 6) In cases

of arterial or venous injuries from major vessels, the outline recommendations above apply

Excessive Tumor Bleeding

Always prepare the instrumentation prior

to tumor removal

The optimal way to prevent bleeding is by preoperative embolization [45, 82, 87] However, this is not always possible Resection should always start in areas not affected by the tumor (e.g., the intervertebral disc), and instrumentation (e.g., screw placement and unilateral rod implantation) should be prepared to allow for a rapid determination of the surgery in the case of hemodynamically relevant bleeding If bleeding occurs, a practical approach is to remove the tumor as quickly as possible, and then to control the bleeding However, this must be planned and coordinated with the anesthetist It is not wise to start tumor removal when the patient is hemodynamically unstable

Postoperative Complications

Surgery does not end with skin closure

Postoperative management is a decisive factor for the success of the surgery It

must be structured and a close communication between the involved specialists

is mandatory

Postoperative monitoring should follow a protocol with regard to:

) blood loss

) required laboratory analyses

) neurological examinations

) vascular examinations

Threshold values for action must be defined (blood loss per hour), as well as

pathways for examination in the case of bleeding or a neurological deficit

Homeostasis Related Complications

Postoperative Bleeding

The amount of blood loss varies considerably with the surgical intervention In

the case of significant or unexpected blood loss detected either by loss through a

drainage system or a decrease of hemoglobin concentration, a vital level of

hemoglobin has to be maintained, and the cause of bleeding must be assessed

The minimal accepted hemoglobin concentration depends on age, comorbidity

and type of surgery As a rule, 6 – 7 g/dl can be accepted in children and 8 – 10 g/dl

in elderly people without comorbidity However, it is important to individually

define the minimally accepted hemoglobin concentration based on the patient’s

general condition and type of procedure (e.g., deformity correction) In elderly

people, the individual risk of stroke, cardiac failure and renal failure must be

con-sidered

A threshold amount (e.g., 600 ml/h) of blood loss from a chest tube or suction

drain is difficult to define and depends on:

The indications for when

to revise depend on the patient and type of surgery

) body weight

) age

) homeostasis

) hemoglobin

) confounding diseases

) availability of blood

) surgical situation

A coagulopathy or bleeding from a large, perhaps tumor infiltrated wound area

cannot be controlled by surgery alone An unexpected major bleeding, not

caused by a coagulopathy, requires imaging, i.e.:

) angiography

) contrast CT

Angiography is the best choice, because interventional closure of a vessel can be

performed Segmental vessels of the spine and vessels supplying a tumor can be

occluded by subsequent coil embolization or stent implantation Contrast CT

scan is less time consuming than angiography, and also provides information

about the bleeding site This method is preferred if bleeding from a large vessel in

the pelvis is suspected, and if the cardiovascular status of the patient allows a

delay

Postoperative Hematoma

In posterior approaches, hematomas normally do not cause major problems The patient is usually lying supine in the early postoperative course, and the pressure

of body weight on the posterior wound does not allow large hematomas to develop The rate of infection in large hematomas is not established, so that clear guidelines of when to evacuate a hematoma cannot be drawn up Even evidence

to use or not to use a closed suction drain is lacking [89]

Retroperitoneal Hematoma

The retroperitoneal space can contain 3-4 L of blood, and can cause an ileus, which can usually be treated conservatively If bleeding has stopped, evacuation will be necessary only in rare cases

Epidural Hematoma with Neurological Deterioration

Epidural hematoma causing

cauda equina compression

requires urgent decompression

Extradural hematomas can be seen relatively often in MRI scans after decom-pressive surgery but seldom cause compression Immediate decompression is required in case of a cauda equina syndrome In elderly patients with extensive decompression, thromboembolic prophylaxis should be started postoperatively instead of preoperatively as a preventive measure (although not evidence based)

Neurological Complications

A thorough postoperative

neurological examination

is a must

It is self-evident that a thorough neurological examination must be performed as soon as the patient is fully awake Neuromonitoring helps but cannot completely avoid neurological complications

Nerve Root Injury

If a nerve root injury is discovered postoperatively, analysis is preferably done by MRI scan A CT scan can show the position of pedicle screws more precisely than MRI Malpositioning of a pedicle screw must be corrected as soon as possible

Spinal Cord Compromise

In the SRS Morbidity and Mortality Report 2003, the incidence of developing a complete paraplegia was 0.1 % related to all spinal operations, and 0.2 % for incom-plete paraplegia Delayed paraplegia developing in the first three postoperative days is rare but does occur [107] Hypotension, hypovolemia and anemia should be avoided in patients who have undergone major corrective surgery In case of a spi-nal cord syndrome, rapid assessment of potential causes is self-evident Spispi-nal cord compression can occur due to an epidural hematoma, implants (hooks, mal-positioning of pedicle screws), bone cement after vertebroplasty, and homeostatic material (Table 6) In case of deformity correction, the correction must be released but it remains a matter of debate whether all implants must be removed

Postoperative Wound Problems

In case of postoperative

fever, rule out wound, lung,

urinary tract and catheter

infection

The prevailing symptom of a wound infection in the immediate postoperative period is:

) fever

However, an elevated temperature (< 39 °C) up to the third postoperative day is

not worrisome and is most often related to a hematoma resorption or

postopera-tive aggression syndrome, although infection parameters should be determined

as a baseline and allow the further course to be judged

According to the CDC (Center for Disease Control and Prevention)

classifica-The differentiation of superficial and deep spinal infections is arbitrary

tion, superficial and deep infections are differentiated A superficial infection is

located in the skin and subcutis, and a deep infection below the muscle fascia

Wound erysipelas is a special form of superficial cutaneous infection, e.g.,

strep-tococci spread by the lymphatic system Deep infections may be dependent on

the presence of an implant [57] Ultrasonography with needle aspiration can be

helpful to distinguish between deep and superficial infection [67] CT scans with

contrast media or MRI scans are often used to demonstrate infections, but there

is no evidence on the sensitivity or specificity available There is also a lack of

published data on the ability of imaging methods to distinguish between

hema-toma and infected hemahema-toma There is a considerable variation in the number of

surgeons applying CDC categories [117] It is also not possible to recommend

In equivocal cases always explore and debride the entire field of surgery

either exploration of the entire wound in every infection or to treat an infection

as a superficial infection until direct proof of a deep infection The probatory

inspection may bring bacteria into contact with an implant if the infection was in

reality suprafacial, and in other cases proper treatment of a deep infection may

be postponed

Superficial Infection

This may cause prolonged wound healing, and occurs in 2 – 3 % of cases in

lum-bar discectomy [93], 0.9 % in lumlum-bar fusion [38] and in more than 5 % in

pediat-ric patients with deformities due to cerebral palsy [109] In the study by Szoke et

al [109], all superficial infections were treated successfully by antibiotics and

local wound care To prevent a superficial infection, pressure to the skin must be

avoided, and also the use of electrocoagulation for skin dissection may increase

the risk Before systemic antibiotic administration, a culture should be taken by

Deep biopsies provide

a more reliable result than a swab

a swab or better a deep biopsy Treatment depends on the cause A widespread

infection, especially erysipelas, is treated by antibiotic administration

Fre-quently, excision of the wound, mobilization of the skin and re-sutures are the

best way to achieve early healing

Deep Infection

Deep infections occur in 2.4 % of spinal fusions [38], and more than 4 % in

pedi-atric patients with deformities due to cerebral palsy [109], and are treated by

debridement, irrigation or hardware removal Early debridement is especially

recommended after instrumented fusion, when clear signs of deep infection are

found Otherwise, biofilm-forming bacteria (staphylococci) can only be

elimi-nated by implant removal Implant removal of long posterior instrumentations

and subsequent use of a brace causes loss of correction [92] Reinstrumentation Titanium implants are less

susceptible to infections and can be left in situ after debridement

in a single stage intervention reduces this risk [80] Titanium implants appear to

be less susceptible to infection than stainless steel implants and can remain in

place if a radical debridement of the wound is performed

Spondylodiscitis

Spondylodiscitis may occur after discography and intradiscal procedures A

dural abscess may develop Fever and severe back pain or neck pain can arise in

the first postoperative days Persistent or increasing back pain after intradiscal

procedures with or without increased infectious parameters should prompt the suspicion of a discitis Incidence is less than 1 % [46, 53, 96, 98] MRI is the imag-ing modality of choice Subsequent to a biopsy to determine the germ, systemic antibiotic treatment is usually sufficient Even an epidural abscess without neu-rological symptoms can be treated this way A psoas abscess or a paraspinal abscess can be drained after percutaneous puncture either under ultrasound or

CT guidance Outcome is usually good but about 50 % progress to spontaneous interbody fusion [76] Open surgical treatment follows the rules outlined in Chapter 36

Persistent Wound Drainage

Rule out infection in case of

persistent wound drainage

The cause of this is either infection or a seroma Ultrasound or other imaging

methods can be used for differentiation Low serum albumin concentration can

contribute as well but it is debatable whether substitution of albumin is helpful Treatment options for postoperative seromas and persistent drainage include observation for spontaneous resolution, external compression by bandages, and wound revision with the aim of closing an empty space Frequent wound disin-fection and proper wound dressing diminish the risk of secondary indisin-fection

Cerebrospinal Fluid Fistula

Small leaks often cause

more problems than large

defects

In the case of wound drainage, a CSF leak must be excluded The diagnosis of a CSF leakage does not cause diagnostic problems if a clear fluid drainage is seen

In unclear cases, the glucose concentration can be determined (50 – 80 mg/

100 ml), which is much higher than in a seroma The CSF production is about

500 ml/day and drainage can therefore be considerable Intermittent CSF loss causes neck stiffness (in 83 %), headache (87 %), nausea, and dizziness Headache will get worse in the upright position, and is ameliorated in the supine position

This so-called hypoliquorrhea syndrome ( Case Introduction) is most often observed in small lesions which form a valve mechanism and hardly ever occur with large defects

The principles of treatment have been outlined above In uncomplicated cases,

a simple stitch over the part of the wound where the CSF is leaking suffices Pro-phylaxis with antibiotics which pass the blood-brain barrier are recommended until wound secretion has stopped and all drains are removed

Vascular Complications

Postoperatively or after angiographic interventions, the arteries have to be moni-tored In arteries supplying the legs, a pulse oximeter can be used for monitoring,

and the leg compartments have to be controlled as well Arterial thrombosis should be managed as an absolute emergency case.

Postoperative Venous Thrombosis

In a recent review by Baron and Albert [5], the rate ranged between 0.3 % and 1 % with the exception of a single study on a small sample size In a Japanese study containing 3 499 patients, it was only 0.1 % [85] In neurosurgical procedures in

2 643 patients and by use of duplex ultrasound scanning, the rate was 6 %, 8 % in craniotomy and 1.5 % in cervical and lumbar spine procedures Of these, 90 % had malignant neoplasms, and 70 % had lower-extremity neuromotor dysfunc-tion [36] Epstein [32] concluded that low molecular weight heparin should be recommended for prevention, but its use must be weighed against the risk of

hemorrhage The duration of prophylaxis remains unclear Our recommendation

is to administer a thromboembolic prophylaxis during the hospital stay and in

high risk patients (tumors, paralysis) If a venous thrombosis is suspected

(swol-len leg, pain), duplex ultrasound is recommended Treatment is the

administra-tion of LMWH and compression stockings for at least 3 months

Pulmonary Problems

Pulmonary Embolism

The rate of fatal lung embolism after spinal surgery is very low

Fatal long embolism is extremely rare According to the Morbidity and Mortality

Report of the Scoliosis Research Society [21], the rate of fatal pulmonary

embo-lism (PE) is0.02% The true rate of non-fatal PE may be underestimated because

of a subclinical course The rate may vary between 0.5 % (posterior surgery) and

6 % (combined anterior/posterior surgery) for adult spinal surgery [23] Typical

signs of PE are:

) chest pain

) pulse acceleration

) insufficient oxygenation

Diagnosis of central pulmonary embolism is made by multi-slice CT scan, and

treatment is usually by high dose low molecular weight heparin

Pneumonia

The incidence of pneumonia after spinal interventions for adult spinal deformity

correction ranges between 1 % and 3.6 % [5] Antibiotic treatment is usually

suf-ficient Overdosage of opioids in elderly patients can result in aspiration

pneu-monia A progression of pneumonia to an adult respiratory distress syndrome

(ARDS) is very rare but can be lethal

Gastrointestinal Problems

Postoperative Bowel Atonia

A large retroperitoneal hematoma increases the risk

of a paralytic ileus

Bowel atonia is a common problem after anterior lumbar approaches and usually

lasts for 3 – 5 days A large retroperitoneal hematoma and a low serum potassium

level increase the risk of paralytic ileus Symptoms are abdominal pain and

vomi-ting Prevention includes minimal invasiveness of the intervention, early oral

feeding [95, 100], peroral fluids on the day of surgery, restriction of intravenous

fluid substitution to 2 000 ml, and early mobilization of the patient There is no

evidence that feeding has to be stopped until bowel movement has started

Treat-ment is by replacing opioid treatTreat-ment by NSAIDs Colon stimulating laxatives

based on bisacodyl and magnesium are recommended, but there are no

prospec-tive trials to support this recommendation The intravenous administration of

metoclopramide or cholinesterase inhibitors (distigmine bromide,

pyridostig-mine bromide) has shown no effect on reducing the duration of postoperative

ileus in any of the prospective studies [17]

Cast Syndrome/Superior Mesenteric Artery Syndrome

Cast syndrome may result from kyphosis correction and must not be missed

After correction of a deformity, especially after correction of kyphosis, the

ascending duodenum may be compressed between the stretched aorta and the

superior mesenteric artery The patient vomits after swallowing food