Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 76 doc

Factors influencing treatment natural history neurologic deficit grade of slippage severity of complaints lumbosacral anatomy duration of symptoms Natural History Low-grade spondyl

Nerve Root Block

A nerve root block can be helpful in deciding equivocal cases of neural compres-sion and radiculopathy (see Chapter 10) Particularly in degenerative spondylo-listhesis, a nerve root block can be also used to support non-operative treatment

Functional Myelography

CT myelography has been surpassed by MRI for the vast majority of indications However, it is helpful in cases with:

) contraindications for MRI (e.g pacemaker) ) functional stenosis

) postoperative (iatrogenic) spondylolisthesis

Particularly in postoperative

spondylolisthesis, myelography and postmyelo-CT are valuable

Myelography alone is of limited use Because a complete block of contrast fluid is occasionally found, the degree of pathology, especially of nerve root compres-sion, is not adequately visualized Without doubt there is the advantage of envis-aging the implications of lumbar flexion/extension for the spinal canal (Fig 5), yet in our opinion the invasive method only has true value if a consecutive CT myelography is performed In cases where a postoperative spondylolisthesis is suspected (Wiltse Type IV), we routinely perform myelography and myelo-CT This enables us to determine the degree of instability as well as the amount of postoperative scarring, which is important for planning surgery

Figure 5 Functional myelography

a,bFunctional myelography of an unstable spondylolisthesis demonstrating a narrowing of the spinal canal in extension

at the level of L4/5 compared to flexion.

Non-operative Treatment

In the management of spondylolisthesis, the spine specialist needs to take into

account various important aspects which will crucially influence the treatment

decision and modality (Table 3):

Table 3 Factors influencing treatment

) natural history ) neurologic deficit

) grade of slippage ) severity of complaints

) lumbosacral anatomy ) duration of symptoms

Natural History

Low-grade spondylolisthesis

in adults is usually

a benign condition with little progression

Some spondylolistheses progress to severe deformities yet are associated with no

or only mild pain and no neurologic deficit and are uncovered only incidentally

Other slips progress very little but produce significant symptoms [30] While

nat-ural history is benign in low-grade adult spondylolisthesis, there is a high

ten-dency for slip progression in children High-grade slips almost always necessitate

surgical treatment; yet low-grade slips can be managed non-operatively in the

majority of cases The risk of slip progression is very high in the presence of a

A rounded sacral dome pre-disposes to slip progression

lumbosacral deformity and a rounded sacrum dome, which often leads to a

high-grade slip and a lumbosacral kyphotic deformity In adults with low-high-grade

spon-dylolytic, degenerative or postsurgical spondylolisthesis (Meyerding I and II),

the natural history of the condition is usually benign [4, 24] While progressive

deformity might well occur due to increase in degeneration at the slipped

seg-ment, the incidence and magnitude of such progression is small [44] Often,

independently of slippage, back pain improves when the disc space has

completely collapsed In only 30 % of these cases does slippage progress, and

about 75 % of the patients who are initially neurologically intact do not

deterio-rate over time [58] These are the patients who will respond to a conservative

treatment Conversely, most patients (about 80 %) with a history of neurogenic

claudication or vesicorectal symptoms deteriorate with poor final outcome [98]

In view of these results, the indications for surgery should without doubt be

stringently met and individualized

In view of this, treatment is dependent on the presence of a neurologic deficit

either caused by a foraminal or a central stenosis Treatment should therefore

also take into account severity and duration of symptoms and comorbidities

With regard to the aforementioned aspects an etiology-based

recommenda-tion of treatment modality can be given (Table 4)

Conservative Treatment Options

The vast majority of spondy-lolisthesis patients can be treated non-operatively

In general, the vast majority of patients with spondylolisthesis can be treated

non-operatively (Table 5)

In patients with favorable indications for non-operative treatment, acute pain

should be controlled with:

) activity modification (bedrest < 3 days)

) pain medication

) anti-inflammatory drugs

) muscle relaxing drugs

Table 4 Guidelines for treatment

Etiology Age Low grade (Meyerding I–II) High grade (Meyerding III–IV)

Asymptomatic Back pain only Back and

neuro-logic symptoms

Back pain only Back and

neuro-logic symptoms

Developmental children no treatment mostly

non-operative

surgical surgical surgical adults no treatment mostly

non-operative

mostly surgical non-operative

or surgical

surgical

Degenerative adults no treatment non-operative

or surgical

usually surgical non-operative

or surgical

usually surgical

Postsurgical children no treatment attempt

non-operative

surgical surgical surgical adults no treatment attempt

non-operative

surgical surgical surgical

Pathologic children depending on

etiology

depending on etiology

depending on etiology depending on

etiology

depending on etiology

depending on etiology Trauma children depending on

slippage

surgical surgical adults surgical surgical surgical

Table 5 Favorable indications for non-operative treatment

) no neurologic deficit ) high patient comorbidity ) tolerable pain threshold ) improvement by exercise program ) short duration of symptoms ) improvement by brace treatment

In patients without neurologic deficit,

a sufficient conservative

management program

is a prerequisite before

surgery is contemplated

This is followed by a therapeutic exercise program with paraspinal and abdomi-nal strengthening to improve muscle strength, flexibility, endurance and balance (see Chapter 21) If pain does not subside sufficiently, the use of a brace or orthoses may be beneficial

Radicular symptoms in spondylolisthesis are a result of a herniated disc or a foraminal stenosis In these cases, non-operative management is not equally suc-cessful when compared to mechanical low back pain However, this does not mean that conservative care is inefficient However, leg pain may require a longer trail of non-operative care to evaluate the efficacy [5] The non-operative treat-ment can be supported by spinal injections (see Chapter 10) to reduce inflam-mation and thus temporarily or even permanently eliminate leg pain:

) epidural blocks ) spondylolysis block ) nerve root blocks

In patients with chronic recurrent back and leg pain a sufficient period of conser-vative management should be performed before operative options are seriously contemplated It is essential that the surgeon is certain that the symptoms are in fact a result of the slippage Non-spinal causes of leg pain need to be contem-plated and excluded

Children and adolescents

with a low-grade spondylolisthesis are usually

treated conservatively

Children and adolescents with a low-grade spondylolisthesis (Meyerding I

and II) are mostly treated non-operatively; yet particularly in adolescence these need to be closely observed, as it is then that they are most likely to progress [12,

33, 51] One of the most important measures for dealing with pain is the

stretch-ing of the hamstrstretch-ings These exercises will improve the clinical condition in the

vast majority of the cases

An acute pars defect can be treated conservatively with a pantaloon cast

In young patients with an acute pars defect, a lumbar brace treatment including

one thigh is a valuable treatment option The rationale is that by minimizing

flex-ion-extension movements of the lumbar spine, the brace will stabilize the acute

fracture allowing the lysis to heal by bony bridging [72] Furthermore the brace

usually diminishes the pain significantly This treatment is performed for

6 – 12 weeks, depending on the age and the symptoms of the patient (Case Study 1)

There are no given rules as to how long non-operative treatment should be

continued Generally speaking, if there is no neurologic deficit, intensive

conser-vative management should be tried over a period of at least 3 – 6 months

How-ever, surgery should not be postponed in patients when clinical symptoms are

concordant with the morphological alterations and an adequate trial of

non-operative therapy has failed

Operative Treatment

General Principles

The choice of surgical treatment greatly depends on the etiology as well as the

degree of slippage as outlined above General objectives of surgical treatment are

to:

) prevent further slip progression

) stabilize the segment

) correct lumbosacral kyphosis

) relieve back and leg pain

) reverse neurologic deficits

Both patient age and degree of slippage differentiate absolute and relative

indica-tions (Table 6):

Table 6 Indications for surgery

Absolute indications Relative indications

) progressive neurologic defits

) slip progression in children/adolescents

) minor, non-progressive neurologic deficits ) radicular and claudication symptoms ) high-grade spondylolisthesis in children

) severe lumbosacral kyphosis with gait

disturbance

) mechanical low-back pain non-responsive

to non-operative care

Progressive slips in children should be treated operatively

High-grade developmental spondylolisthesis in adolescents should almost

always be treated operatively Those presenting with a sciatic crisis known as the

Phalen-Dixon sign need immediate medical attention in the form of intravenous

analgesics, bedrest and close neurologic monitoring If the severe pain does not

subside quickly or neurologic deficit is observed, early surgical management

should be strived for It must be pointed out that high-grade spondylolisthesis

with either lysis or elongation of the pars constitutes a treatment challenge for

even the most careful surgeon [94] High-grade spondylolisthesis (Meyerding III

and IV) in adults is treated according to the symptoms and biological age of the

patient While the young, otherwise healthy adult will biomechanically benefit

from correction of deformity parameters and realignment of the spine with the

sacrum, the elderly patient with comorbidity may only need decompression

Although Möller and Hedlund [69] were able to show that surgical management There is no general

consensus on the optimal treatment regime for adult spondylolisthesis

of adult spondylolisthesis can provide favorable clinical outcomes compared to a

supervised exercise program, there is no general consensus as to what constitutes

the optimal non-operative or operative treatment regime The decision to

recom-mend surgery to an adult patient with spondylolisthesis must therefore be indi-vidualized very carefully Almost all cases of traumatic spondylolisthesis in the adult will need surgical management

Surgical Techniques Spondylolysis Repair

An acute pars defect

can be directly repaired

by osteosynthesis

In symptomatic cases with a very slight slippage and a verified fresh pars defect,

an osteosynthesis using the Morscher screw and hook [35, 73] or direct repair by screw fixation (Buck’s fusion [6, 14]) (Fig 6) or figure of eight wiring (Scott’s

technique [19, 96]) may be justified.

Each fixation technique significantly increases stiffness and returns the inter-vertebral rotational stiffness to nearly intact levels Importantly the displacement across the defect is significantly suppressed by all these instrumentation tech-niques; yet the least motion is allowed with the screw-rod-hook fixation or Buck’s technique [19], making these the method of choice The prognosis for these tech-niques is primarily determined by the time of surgery and whether displacement has already taken place Overall direct osteosynthesis seems to be a compara-tively safe and effective treatment method, independent of which method is uti-lized in cases with spondylolysis and fresh pars defects [19, 124]

Decompression

When decompression with

laminectomy is performed,

fusion is compulsory

While a symptomatic disc herniation in the segment L4/5 with coexistent slip at L5/S1 can be treated by selective microsurgical decompression at L4/5 alone, a discectomy in the olisthetic segment should be avoided due to a high risk of addi-tional destabilization Due to the nature of the slippage, foraminal stenosis can-not be addressed selectively without causing added instability If neurologic

symptoms necessitate decompression and a complete laminectomy (Gill’s

proce-dure [80]) is done, fusion is mandatory because of the destabilization.

Care should be taken that all proliferative pseudarthrosis tissue is removed after the nerve roots have been identified While neurologic deficit is a definite indication for decompression, there is an ongoing discussion as to whether in the face of radicular symptoms decompression is always necessary [44] The argu-ment against decompression relates to the loss of the tension-band strength and subsequent potential instability that the removal of posterior elements may exac-erbate [44] Long-term follow-up studies have shown that especially in children repositioning of the slippage by instrumentation can improve leg pain very soon after surgery [46]

Instrumented Versus Uninstrumented Fusion

For many years, uninstrumented fusion in situ has been the gold standard for

the treatment of isthmic spondylolisthesis in children and adolescents [117] and still has strong advocates [91] However, with the advent of pedicular fixation devices, many spine surgeons have now changed to an instrumented fusion because it facilitates aftertreatment [11, 13, 43, 47, 92, 105]

Outcome of instrumented

fusion is not shown

to be superior to non-instrumented fusion

While the surgeon may well have the impression that instrumentation gives good primary stability and allows for a more precise realignment of the spinal column, studies randomizing isthmic spondylolisthesis patients with and without pedicle screws have not shown an improved fusion rate or improved clinical outcome with reduction and instrumentation [8, 62, 69] The argument that a better realignment may be achieved with pedicle screws may be true but remains unproven

e f

a

b

e

Figure 6 Direct spondylolysis repair

aIsthmic spondylolisthesis at the level of L4/5 (arrow).bReversed gantry CT demonstrating the bilateral spondylolysis.

c, dDirect screw fixation and bone grafting of the defect.e, fSolid fusion of the defect at 1 year follow-up with complete

resolution of pain (Courtesy of University Hospital Balgrist).

For the posterolateral fusion, the spine can be approached either by a midline skin

incision or alternatively by bilateral muscle-splitting (Wiltse approach [117]) The

transverse processes should be thoroughly denuded and decorticated, along with the lateral aspect of the facet joint and pedicle (see Chapter 20) Especially at the upper margin of the fusion, destruction of the facet joint should be avoided to avoid damage to the adjacent motion segment Autologous cancellous bone should be packed over the transverse processes, the lateral facet joints and, if a mid line incision has been performed, along the decorticated spinous processes

of the slipped motion segment Bone is usually obtained from the iliac crest, though this may of course increase morbidity

The mainstay of surgery

in children is spinal

realignment and

in the elderly patient

spinal stabilization and decompression

In contrast to treatment of adolescents and young adults where a primary aim

of surgical treatment is correction of deformity and spinal realignment, the mainstay of surgery in the adult and elderly patient is decompression, whereby the aim is to relieve radicular and claudication symptoms (see Chapter 19) There is no general consensus about the indications for fusion surgery, the goals being to relieve back pain from a degenerated disc and facet joint by elimination

of the instability Indications for instrumentation are even more controversial [99], due to the higher complication rate

Slip Reduction

The treatment of high-grade spondylolisthesis differs between children and adults, as does that of low- and high-grade slips in adults In low-grade slips it remains uncertain whether an attempt to reduce the anterior slip is actually nec-essary or desirable Often some degree of reduction is already achieved by the prone position and subsequent exposure of the spine [71]

In adult spondylolisthesis

in situ fixation is a proven

surgical method

In high-grade slips in the adult, in situ fixation with or without

decompres-sion, depending on the neurologic status, is a proven surgical method [20], espe-cially when intervertebral body space has markedly diminished Reduction of the slipped vertebra remains controversial in this patient group [13, 33] Consensus exists on the fact that partial reduction of the slip angle should be attempted if significant malalignment and foraminal stenosis is present The aim is to decom-press neural structures, decrease the lumbosacral kyphosis and facilitate fusion

In cases where partial reduction has been achieved, anterior structural support should be contemplated to hold the reduction in place [20]

In children the aim

of surgery is to correct

sagittal alignment and lumbosacral kyphosis

Especially in high-grade slips (Grade III–IV) in children, the aim of surgery is

to correct sagittal alignment and lumbosacral kyphosis By improving the bio-mechanics, the chances of solid fusion are significantly increased (Case Study 2) Nonetheless the procedure remains a surgical challenge especially in view of the high complication rates ranging from 10 % to 60 % [11, 13, 21] This has led some surgeons to perform in situ posterolateral spine arthrodesis for high-grade slips

in children [12, 28] with satisfactory clinical results

Interbody Fusion

Spondylolisthesis is per se a spinal instability and as with all forms of osteosyn-thesis good postoperative stability is needed to avoid non-union or implant

Interbody fusion

is recommended when

reduction and/or distraction is performed

breakage Especially when repositioning and/or distraction is performed, an interbody structural support of the anterior column is crucial [11] In cases where the anterior column has not been addressed biomechanically, fusion rates for posterolateral fusions vary from 100 % [11, 29, 92] to as low as 33 % [41, 50, 111] Even in cases where fusion has been verified, authors report on patients who continue to suffer from what is presumed to be “discogenic back pain” [3, 47]

b

c

d

Case Study 2

A 10-year-old patient presented with hyperlordosis of the lumbar spine, sagittal malalignment (lumbosacral step-off ),

flexed knee position, tight hamstrings and paraspinal muscle spasm (a) The patient was neurologically intact CT and

MRI of the lumbar spine demonstrated a spondyloptosis (b) Note the dome shaped sacrum (b,c) The patient did not

exhibit a spondylolysis but an elongated pars (c) Surgery was performed to realign the spine by means of sacral dome

osteotomy (for technique seeFig 7), pedicular instrumentation at L4–S1, posterolateral fusion at L4/5 and interbody

fusion at L5/S1 with correct sagittal realignment (e,f) At the latest follow-up, the patient was symptom free and had

sub-stantially improved her sagittal balance (Courtesy of University Hospital Balgrist).

Table 7 Results of surgical treatment of high-grade spondylolisthesis with and without instrumentation

Author Cases Type of

spondylo-listhesis

Patient age

Follow-up

Technique Complications/

outcome

Conclusions

Schuffle-barger

et al.

(2005)

[85]

18 adoles-cent high-grade develop-mental

14 (10 – 16) years

3.3 (2.3 – 5) years

Gill decom-pression, monosegmen-tal PLIF with Harm’s cages and autoge-nous iliac graft

2 structural complica-tions

Retrospective study

0 neurologic complica-tions

PLIF procedure provides near-anatomic correction of high-grade spondylolisthesis with-out significant complications Anterior column support and posterior compressive instru-mentation help restore bio-mechanics and allow fusion

0 infections

0 pseudarthrosis

0 reoperations

Grzegor-zewski

et al.

(2000)

[23]

21 adoles-cent high-grade develop-mental

14.9 (9.4 – 19.3) years

12.8 (6 – 24.8) years

PLF + iliac bone graft + immobiliza-tion in panta-loon cast

4 months

0 neurologic complica-tions

0 pseudarthrosis

Retrospective study

5 patients showed pro-gression of slip 1 year postop.

In situ posterolateral arthrod-esis with large amount of bone graft followed by immo-bilization provides satisfac-tory results

Molinari

et al.

(2002)

[62]

37 adoles-cent high-grade develop-mental

13.5 (9 – 20) years

3.1 (2 – 10.1) years

PLF (n = 18) vs.

circumferen-tial (n = 19)

fusion

39 % pseudarthrosis for posterolateral proce-dure vs 0 % in circum-ferential fusion

Retrospective study All patients who had pseudar-throsis achieved solid fusion with a second procedure involving 360° fusion with ante-rior column structural grafting Möller

et al.

(2000)

[64]

77 adult low grade

39 (18 – 55) years

2 years PLF with

(n = 37) vs.

without

(n = 40)

trans-pedicular fixation

no significant differ-ence in fusion rate

This prospective randomized trial suggests that the use of supplementary transpedicular instrumentation does not add

to the fusion rate or improve clinical outcome

level of pain as well as functional disability were very similar Bjarke

et al.

(2002)

[7]

129 adult low grade

46 and 43.5 (20 – 67) years

5 years PLF with

(n = 63) vs.

without

(n = 66)

trans-pedicular fixation

instrumented group had 25 % reoperation rate vs 14 % for non-instrumented

This prospective randomized trial showed that long-term functional outcome improved

in both groups Isthmic spondy-lolisthesis profited from non-in-strumentation while degenera-tive spondylolisthesis fared bet-ter with transpedicular fixation

functional outcome similar in both groups

Suk et al.

(2001)

[94]

56 adult low grade

45.9 and 51.3 (23 – 70) years

2 years PLF with

instrumenta-tion (n = 35) vs.

ALIF with ped-icle screw

fixa-tion (n = 21)

no difference in complication rate clinical outcome iden-tical

Prospective study

PLF led to significant loss of reduction

ALIF with pedicle screw instrumentation was superior

to PLF with instrumentation

in terms of preventing reduc-tion loss for spondylolytic spondylolisthesis Kim et al.

(1999)

[40]

40 adult low grade

±42 (21 – 62) years

2.3 – 3.6 years

ALIF (n = 20)

vs PLF with

instrumenta-tion (n = 20)

fusion rate after

12 months over 90 % for both methods

Retrospective study

satisfactory clinical results in 85 % for ALIF and 90 % for PLF + instrumentation

There was no statistically sig-nificant difference in clinical results between the two methods

Brad-ford

et al.

(1990)

[12]

22 adult high grade

5 (2 – 7.5) years

First posterior decompres-sion + PLF + halo-traction, then in sec-ond proce-dure ALIF

percentage of slippage pre- vs postop did not change substantially

Retrospective study

4 patients had non-union

Alignment of the sagittal plane was restored in

17 patients Back pain and radicular symptoms were relieved in all but one patient postop 1 cauda

equi-na syndrome and 2 nerve root neuropathy, yet persisting neurologic deficit in only 1 patient

at follow-up

Table 7 (Cont.)

Author Cases Type of

spondylo-listhesis

Patient age

Follow-up

Technique Complications/

outcome

Conclusions

Boos

et al.

(1993)

[10]

10 adult high

grade

4.7 (3.6 – 6.3) years

PLIF and PLF

(n = 6) vs PLF (n = 4)

5/6 patients with sole PLF had loss of reduc-tion, non-union and implant failure

Retrospective study

all patients with PLF + PLIF had fusion and

no loss of reduction

PLF + PLIF for spondyloptosis is

a technically demanding pro-cedure Permanent reduction and fusion is only obtained with combined interbody and posterolateral fusion Roca

et al.

(1999)

[77]

14 adult high

grade

21 years 2.5 years Lumbosacral

decompres-sion + PLF + interbody fusion

6 patients with tran-sient motor deficit

Retrospective study

2 pseudarthrosis

Circumferential arthrodesis through a posterior approach

is a safe and effective tech-nique for managing severe spondylolisthesis

13 excellent clinical results

Fusion techniques can achieve posterior column stability, anterior column stability or both

The fusion techniques available for this deformity can conceptually be divided

into those that achieve posterior column stability, those that achieve anterior

col-umn stability and combined approaches that achieve both In cases where the

spinal canal has to be decompressed and instrumentation is planned, it makes

sense to perform a posterior lumbar interbody fusion (PLIF); yet this is certainly

not mandatory (Case Introduction) The choice of which approach to take will

heavily depend on personal preference and familiarity with the approach,

resources and infrastructure as well as back-up expertise in case of

complica-tions

Anterior interbody fusion allows better disc removal and fusion

Anterior techniques in spine fusion allow for a complete discectomy and very

precise placement of an interbody implant or graft Particularly the latter aspect

is an advantage of the method, as larger structural grafts can be placed without

the danger of dural sheath damage or nerve root injury While disc height may

thereby be restored and kyphosis diminished, there is ongoing discussion as to

whether an adequate repositioning and thus improvement of sagittal alignment

of the spine can be achieved by a single anterior procedure, with or without

instrumentation Also, because nerve root and dural sac are not decompressed

before the repositioning maneuver, there is a high likelihood of neurologic

injury The method should therefore only be contemplated in low-grade

olisthe-sis, where the primary aim is in situ stabilization and fusion without

decompres-sion or repositioning in neurologically asymptomatic patients

In the lumbar spine the anterior technique usually involves a retroperitoneal

approach, with its attendant complications such as possibility of vascular injury,

damage of the sympathetic plexus with subsequent retrograde ejaculation in

males, as well as damage to retro- and intraperitoneal structures Spine surgeons

performing this approach should therefore either be able to manage possible

complications themselves or have very fast access to expertise

Circumferential arthrodesis offers the highest fusion rate

Circumferential stability offers all the advantages of both the aforementioned

techniques, yet obviously also incorporates the possible complications

Com-bined approaches can be either posterior or transforaminal interbody fusion

(PLIF or TLIF) or anterior lumbar interbody fusion (ALIF) with posterolateral

intertransverse fusion (PLF) Due to the high degree of primary stability

achieved with the 360° treatment of the spine, fusion rates are highly reliable

with numerous reports claiming rates of 100 % [34, 100, 104, 123] Also, an

excel-lent spinal realignment can be achieved Despite these good results, the

tech-nique of 360° instrumentation is technically more demanding than ALIF or PLF

alone