Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 80 pdf

Posterior Approach The basic steps of the classical posterior procedure for Scheuermann’s kyphosis are: posterior release correction and internal fixation using posterior instrumentati

Kyphosis correction by anterior instrumentation and fusion has been performed

in some centers very recently The aims are to save spinal segments and to avoid

damage to the paraspinal muscles There are, however, no reports yet on the

out-come of this procedure.

Posterior Approach

The basic steps of the classical posterior procedure for Scheuermann’s kyphosis

are:

) posterior release

) correction and internal fixation using posterior instrumentation

) posterior fusion with bone graft

Spinal cord monitoring and the possibility for a wake-up test are absolutely

indis-pensable for a safe surgical correction of the kyphotic deformity.

Posterior Release, Correction, and Fusion

The goal is shortening of the posterior column to allow for extension of the spine.

The posterior release encompasses the resection of:

) spinous processes

) ligamenta flava

) upper and lower margins of the laminae

) facet joints

in the area of the deformity (usually four to six segments) (Fig 9b, c).

Instrumentation includes the upper kyphosis end vertebra and the first lordotic segment

Instrumentation and correction of the deformity follow the cantilever and

poste-rior tension bend (compression) principle The uppermost instrumented

verte-bra is the upper end verteverte-bra of the deformity Distally, the first lordotic segment

caudal to the apex should be included [39, 40, 41, 53, 56].

Claw constructs or pedicle screws are used above the apex of the deformity,

pedicle screws in the lower part of the instrumentation A two-rod construct

(Case Study 2) or a four-rod construct can be used for the correction maneuver

(Fig 10a, b) Stiff rods should be chosen to minimize the risk of loss of correction.

Figure 10 Cantilever technique

Instrumentation/correction using cantilever and posterior tension band principle:atwo-rod technique andbfour-rod

technique

a b

c

Case Study 2

A 16-year-old male student was admitted for

assessment and treatment of thoracic

hyperky-phosis The patient had no earlier treatment or

radiographs The deformity had developed

dur-ing 3 years He complained about mild

thoraco-lumbar pain after exercising and was dissatisfied

with the cosmetic appearance of his back

Other-wise, he was healthy Clinically, he exhibited the

typical features of Scheuermann’s kyphosis in

the lower thoracic spine (a–c) The deformity was pain free and corrected partially in extension Bilateral hamstring tight-ness of 50 degrees was present, and there were no pathologic neurological signs On the standing lateral radiograph, thoracic kyphosis measured 95 degrees (d) It corrected to 54 degrees on the supine extension film (e) Around the apex (T8) there were five wedge vertebrae The standing posteroanterior radiograph was normal (f) MRI showed typical Scheuermann’s changes, and no cord compression or other pathology (g)

During the correction maneuver the area of the release should be watched very carefully to detect and avoid cord compression due to translation of the vertebrae

or kinking of the laminae The interlaminar gaps should not be fully closed at the end of the correction maneuver to allow for drainage of possible hematoma After instrumentation the posterior elements of the area are decorticized with

h i j k

Case Study 2 (Cont.)

As the deformity was relatively mobile, brace treatment was considered It was, however, discarded because of the

mini-mal remaining spinal growth left (Risser 4, skeletal age 18 years) A posterior release, Universal Spine System (USS)

instru-mentation/correction using the two-rod cantilever tension band principle, and a posterior fusion from T2 to L2 were

per-formed There were neither intraoperative nor postoperative complications The cosmetic result looked very satisfactory

(h,i) On radiographs 6 months after operation, thoracic kyphosis measured 48 degrees (j, k).

great care and packed with autogenous or allogenous bone graft to achieve a

thick solid fusion mass Spinal cord monitoring and/or wake-up test are

manda-tory Prophylactic antibiotics are recommended.

Combined Anterior/Posterior Approach

A combined anterior/poste-rior approach is indicated in very rigid kyphosis

In very rigid severe deformities, especially in adult patients, a combined

approach may be considered (Fig 9d) However, there are no scientifically based

numeric data available informing the surgeon which cases need additional

ante-rior release and which can be treated by posteante-rior approach only Halo-femoral

traction, used by some authors during the interval between staged anterior and

posterior surgery, does not seem to improve final results [12, 29].

Through an anterior approach the rib heads, the anterior longitudinal

liga-ment, the intervertebral discs down to the posterior longitudinal ligaliga-ment, and

the cartilaginous vertebral endplates in the area of the deformity are resected.

The disc spaces are distracted and filled with bone graft (morcellized rib)

Tradi-tionally, this has been performed through a thoracotomy as an open procedure.

The literature has shown that thoracoscopic anterior release is effective in

Scheuermann’s kyphosis [1] Its definitive advantages over classic open thoracot-omies are cosmesis and less morbidity It does, however, have a considerable learning curve [45].

Results of Operative Treatment

Surgery provides

a favorable outcome

in selected cases

Outcome data after operative treatment of Scheuermann’s kyphosis comprise mainly retrospective short-term or mid-term follow-up reports Results are ana-lyzed usually according to the two major indications for which the surgery was

carried out: pain and deformity As far as pain is concerned, all series report an

improvement in the amount of back pain of between 60 % and 100 % [12, 15, 29,

31, 60] Hosman et al showed a marked improvement concerning back pain in 31 out of 33 patients after a mean follow-up of 4.5 years However, neck pain did not seem to have improved after surgery Interestingly, no relationship between the amount of correction and the amount of residual back pain was found As far as patients’ satisfaction is concerned, most series report a very high satisfaction rate

of up to 96 % [31].

As no cosmetic scale has been available for the assessment of juvenile kypho-sis, one has to judge the cosmetic correction on plain radiographs, which

repre-sent an extrapolation of the cosmetic results The rate of correction given in the

different surgical series is 21 – 51 % Loss of correction in the instrumented area

is minimal at present due to the rigidity of instrumentation systems used ( Table 8) Ideally, the result of correction of juvenile kyphosis should be assessed

according to patient satisfaction and improvement of perceived self-image and independent judgement of clinical photographs before and after the surgery by non-medical observers The literature definitively lacks such information The results of corrective surgery should not be based on Cobb angle correction alone but rather on outcome instruments such as the SRS 24, the sagittal balance of the patient, and the assessment of spinal mobility and function So far, only Poolman

et al have used the SRS questionnaire instrument, which includes assessment of the cosmetic situation [56].

Table 8 Surgical treatment of juvenile kyphosis

Author N Technique Follow-up

time (months)

Kyphosis (degrees)

Outcome/complications Conclusions

Bradford

et al

(1974)

22 post Harrington compression

35 (5 – 92) pre 72 (50 – 128) pain relief 100 %, cosmesis

improved 100 %

complications frequent

cast for 9.8 months

follow-up 47 (29 – 88)

pseudarthrosis 3, infection 1, thromboembolia 1, neurologi-cal 1

indication restricted to patients with severe pain

approach to avoid loss

of correction

loss > 10 in 15/22 patients Taylor et

al (1979)

27 post Harrington compression

26.6 (6 – 72) Pre 72 (55 – 93) pain relief 100 %, cosmesis

improved 100 %

instrument/fusion too short leading to loss of correction

cast for

5 months

follow-up 46 (23 – 63)

new neck/shoulder pain 9/27 patients

recommendation to fuse whole curve correction: 36 % intraoperative lamina fracture 1,

pneumothorax 1, donor-site hematoma 3, transient paresthesia

1, gastrointestinal obstruction 1 loss of correction:

in fusion: 7 outside: 12

Table 8 (Cont.)

Author N Technique Follow-up

time (months)

Kyphosis (degrees)

Outcome/complications Conclusions

Bradford

et al

(1980)

24 anterior release 24 – 68 pre 77 (54 – 110) hook site pain 2, fusion extended

for pain 1, pulmonary embolus/

deep femoral thrombosis 2, deep infection 1, vascular obstruction

of duodenum 1, hematothorax 1, pericardial effusion 1, pseudar-throsis 1, intercostal neuroma 1, discomfort at lower hook 3 (2 removed)

correction after com-bined approach supe-rior to antesupe-rior only but greater morbidity

Halo traction

2 weeks

follow-up 47 (30 – 67) post Harrington

compression

correction: 39 % Risser cast

9 – 12 months

loss of correc-tion: mean 6 outside fusion:

13 – 25 in 5 patients Herndon

et al

(1981)

13 anterior release 29 (12 – 66) pre 78 (61 – 95) pain relief in 8/13 patients,

cos-mesis improved 100 %

significant risk of severe complications Halo traction

2 weeks

follow-up 45 (30 – 73)

mortality 1, instrumentation problems 2, transient neurology

1, pressure sore 1, urinary reten-tion 1, deep thrombosis 1, psy-chological problems in halo 1

no advantage from preoperative halo;

deformities over 70°

need combined approach post Harrington

compression

correction: 51 % Risser cast

6 months

Lowe

(1987)

24 anterior release 32 (19 – 48) pre 84 (72 – 105) pain relief in 18/24 patients,

cosmesis improved 100 %

longer follow-up neces-sary

Halo gravity

1 week

follow-up 49 (30 – 65)

transient hyperesthesia of trunk and lower extremity 4, rod removal for bursa 4, fusion too short distally 2, rod migration 1

hyperesthesia worri-some

posterior Luque

double rod

accep-tance

no external

sup-port

loss of correc-tion: mean 5 Lowe and

Kasten

(1994)

32 anterior release

+ posterior

Cotrel-Dubous-set

instrumen-tation in 28

patients

42 (24 – 74) pre 85 (75 – 105) preoperative back pain 27/28

patients, at follow-up 18/28 mild back discomfort with vig-orous activities

indication for surgery symptomatic kyphosis

> 75°

4 patients post

C-D only

follow-up 47 (24 – 65)

cosmetically satisfied 26/28 patients

negative sagittal bal-ance in Scheuermann’s correction: 45 % proximal junctional kyphosis

26° (12°–49°) in 10/28 patients due to overcorrection (> 50 %)

or short fusion

avoid overcorrection to avoid junctional kypho-sis

loss of correc-tion: 4 (0 – 19)

distal junctional kyphosis 17°

(10°–30°) in 9/28 patients due to short fusion

include proximal end vertebra and first lor-dotic segment distally sagittal balance:

pre –5.3 cm follow-up –6.6 cm Otsuka et

al (1990)

10 posterior heavy

Harrington

compression

27 (18 – 33) pre 71 (63 – 90) pain relief 100 %, cosmesis

improved 100 %

good cosmesis improvement and pain relief

Brace

6 – 9 months

follow-up 39 (28 – 57)

rod breakage after motor vehi-cle accident 1, intraoperative lamina fracture 1

in flexible kyphosis (bending to < 50°) pos-terior surgery only is sufficient

correction 45 % lung problems in patient with

preoperative congenital obstructive lung disease 1 loss of

correc-tion: 8

Fusion too short 3

in 3/10 patients loss > 10

Table 8 (Cont.)

Author N Technique Follow-up

time (months)

Kyphosis (degrees)

Outcome/complications Conclusions

Reinhardt

and

Bassett

(1990)

14 post Harrington compression

32 (12 – 65) pre 71 (54 – 101) clinical outcome and

complica-tions not mentioned

to avoid junctional kyphosis, fusion beyond the end verte-bra to a non-wedged (“square”) vertebra nec-essary

anterior release

in 6/14 patients

follow-up 37 (15 – 54)

distal junctional kyphosis 23°

(15°–31°) in 5/14 patients cast or brace for

6 months

correction: 48 % proximal junctional kyphosis

34° in one patient loss of

correc-tion: 8 (4 – 14) Poolman

et al

(2002)

23 anterior release 75 (25 – 126) pre 70 (62 – 78) SRS outcome instrument at

fol-low-up: total score 83 (55 – 106),

7 patients < 72

outcome relatively fair

post Cotrel-Dubousset 13/23

follow-up 55 (36 – 65)

back pain increased 4, back pain improved 10, self-image improved 10, self-image wors-ened 3, would have the proce-dure again 16, no correlation SRS score vs radiography

loss of correction after implant removal

Moss-Miami 10/23

correction: 21 % aorta + thoracic duct lesion 1,

proximal junctional kyphosis 3, screw breakage 3, painful hard-ware 6

indication for surgery questioned

loss of correc-tion: mean 15°

in 8 patients after rod removal Hosman

et al

(2002,

2003)

33 posterior H-frame instru-mentation

A Post only

50 (25 – 93)

A + B Pre 79 (70 – 103)

Oswestry Disability Index Pre 21.3 (0 – 72), follow-up 6.6 (0 – 52)

good radiographic and clinical results No bene-fit from anterior release Excessive correction should be avoided to minimize risk for postop-erative sagittal malalign-ment

anterior release

in 17/33 patients,

B Combined

55 (24 – 98)

follow-up 52 (32 – 81)

no difference if compared pos-terior only versus combined sur-gery

orthosis

3 months

correction: 34 % cosmesis improved 100 % loss of

correc-tion: mean 1.4°

infection 3, instrumentation removal for prominence or irri-tation 4, loss of distal fixation (reop.) 1, rod breakage 1, proxi-mal junctional kyphosis 1

patients with ham-string tightness have significantly higher risk for postoperative sagit-tal imbalance

no difference A

vs B

Complications

Operative kyphosis

correction carries the risk

of major complications

Surgery on juvenile kyphosis is not benign and complications can occur Neu-rological complications due to spinal cord compression can arise during the correction maneuver because of a rare but preoperatively undetected

intraspi-nal problem, or due to a surgical technique failure The exact rate of neurologi-cal complications is not known in surgery of juvenile kyphosis Probably, it

is higher than for idiopathic scoliosis operations Possible complications such

as death, dura lesion, vascular lesion, lamina fracture, Brown-S´equard syndrome, pulmonary problems, venous thrombosis, gastrointestinal ob-struction, infection, instrument failure, and pseudarthrosis have been described as in any major corrective procedure for spinal deformities [2, 4, 12,

15, 29, 39, 53, 56].

Postoperative sagittal

imbalance must be avoided

Proximal junctional kyphosis due to overcorrection occurs in 20 – 30 % of

cases according to Lowe and Kasten [41] Distal junctional kyphosis due to short

fusion causing loss of correction (“adding on”) outside the instrumented area has been reported by several authors [12, 26, 29, 41, 58, 67] Reinhardt and Bassett

saw distal junctional kyphosis if fusion was carried out to a wedged caudal end

vertebra of the kyphosis They recommend including the next “square” vertebra

to allow smooth transition into lumbar lordosis [58] Lowe postulates three

pos-sible mechanisms: firstly, fusion that is too short, distally stopping above the first

lordotic disc, results in distal junctional kyphosis; secondly, fusion that is too

short proximally and does not include the whole kyphosis on the top may cause

proximal junctional kyphosis and a goose neck appearance Finally,

overcorrec-tion seems to be a factor and one should not correct the kyphosis to more than

50 % of its initial value [40] In the case of overcorrection, possibly the remaining

mobile segments below the fusion are unable to adapt to the alignment changes

caused by excessive kyphosis correction As a result this leads to permanent

increased flexion stress on the segment adjacent to the fusion, finally causing its

breakdown This view is supported by Hosman et al [30], who stressed the

importance of tight hamstrings for surgical correction.

According to Poolman et al., significant loss of correction occurs after removal

of the instrumentation even if the fusion is healed [56] Therefore, the metal

should not be removed if it is not imperative to do so, e.g in the case of infection.

The benign natural history must be weighed against the risks of the surgery

Overall, surgery in Scheuermann’s kyphosis bears the risk of serious

complica-tions, a risk the surgeon should be aware of The benign nature of the deformity

should be kept in mind, and the risks and benefits of an operation should be

weighed up carefully.

Recapitulation

The sagittal alignment of the human spine

devel-ops during growth and shows great individual

vari-ability The range of thoracic kyphosis in healthy

people ranges from 10 to 60 degrees There are no

evidence-based “normal values”.

Definition and epidemiology. “Classic” juvenile

ky-phosis (Type I) is a rigid thoracic or thoracolumbar

hyperkyphosis due to wedge vertebrae

develop-ing durdevelop-ing adolescence The incidence is 1 – 8 %

ac-cording to the literature Atypical juvenile kyphosis

(Type II, “lumbar” Scheuermann’s kyphosis) affects

mainly the lumbar spine, is characterized by

end-plate changes of the vertebral bodies without

sig-nificant wedging, and leads to loss of lumbar

lordo-sis (flat back).

Pathogenesis The exact etiology is unknown

Ge-netic, hormonal, and mechanical factors have been

discussed A disturbance of the enchondral

ossifica-tion of the vertebral bodies leads to wedge

verte-bra formation, causing increased kyphosis Type II is

frequently seen in athletes as a sequela of axial

overloading.

Clinical presentation. A rigid thoracic

hyperkypho-sis with or without pain is the reason for

consulta-tion Hamstring tightness is common Abnormal neurological signs are rare In Type II, the lumbar spine is stiff and pain symptoms are more promi-nent.

Diagnostic work-up. Diagnosis is based on typical changes seen on lateral standing plain radiographs:

hyperkyphosis, irregularity of the endplates, wedged vertebrae, increased sagittal length on the

vertebral bodies, and narrowed disc spaces.

Schmorl’s nodes may be present but they are not pathognomonic MRI is taken if abnormal neuro-logical signs are observed or in connection with preoperative work-up.

Non-operative treatment. The general objectives

of treatment are to prevent progression of the kyphosis, to correct the deformity, and to relieve pain The choice of treatment must consider the natural history, which is benign in the majority of

cases In Type I, back pain is common but

usu-ally mild Type II and kyphosis of greater than 70 de-grees causes more clinical symptoms Pulmonary compromise occurs only in severe deformities (> 100 degrees) Bracing and casting are effective in mobile deformities of between 45 and 60 degrees if

at least 1 year of growth is left.

Operative treatment. The only absolute indication

for surgery is a neurological compromise (spastic

paraparesis) Kyphosis greater than 75 degrees,

pain, and severe cosmetic impairment are relative

indications The benign natural history should be

kept in mind and overtreatment must be avoided.

Posterior correction, instrumentation and fusion

are sufficient in the majority of cases In very severe

rigid deformities a combined approach with addi-tional anterior release can be considered The oper-ative results are good in most cases concerning pain relief and cosmesis Severe intra- and postop-erative complications have been described The risks and benefits of operative treatment must be weighed carefully against the benign natural his-tory.

Key Articles

Arlet V ( 2000) Anterior thoracoscopic spine release in deformity surgery: a meta-analy-sis and review Eur Spine J 9 Suppl 1:S17–23

This is a meta-analysis of all the literature available on thoracoscopic spine release done for scoliosis or kyphosis Thoracoscopic release has been effective in kyphosis for curves with an average of 78 degrees that were corrected after video-assisted thoracoscopic release and posterior surgery to 44 degrees No report of the surgical outcome (balance, rate of fusion, rib hump correction, cosmetic correction, pain, and patient satisfaction) was available for any series

Bernhardt M, Bridwell KH ( 1989) Segmental analysis of the sagittal plane alignment of the normal thoracic and lumbar spines and thoracolumbar junction Spine 14:717–21

This is a review of the normal sagittal alignment of the spine segment by segment in 102 healthy individuals, indicating that there is a wide range of normal sagittal alignment of the thoracic and lumbar spines The thoracolumbar junction is for all practical purposes straight; lumbar lordosis usually starts at L1 – 2 and gradually increases at each level cau-dally to the sacrum

Hosman AJ, de Kleuver M, Anderson PG, van Limbeek J, Langeloo DD, Veth RP, Slot GH ( 2003) Scheuermann kyphosis: the importance of tight hamstrings in the surgical cor-rection Spine 19:2252–9

The author reviewed 33 patients with juvenile kyphosis who underwent surgical correc-tion Sixteen patients had tight hamstrings, and 17 patients had non-tight hamstrings Hamstrings were considered tight if the popliteal angle was > 30 degrees Patients with

tight hamstrings had a significantly greater risk of postoperative imbalance (p< 0.05).

Tight hamstring patients can be classified as “lumbar compensators” and as such are prone to overcorrection and imbalance

Hosman AJ, Langeloo DD, de Kleuver M, Anderson PG, Veth RP, Slot GH ( 2002) Analysis

of the sagittal plane after surgical management for Scheuermann’s disease: a view on over correction and the use of an anterior release Spine 2:167–75

A cohort of 33 patients who had undergone surgery for their Scheuermann’s

kypho-sis were reviewed: Group A: posterior technique (n = 16); Group B: anteroposterior technique (n = 17) At follow-up evaluation (4.5±2 years) there was no difference in

curve morphometry, correction, sagittal balance, average age, and follow-up period between Groups A and B In reducing postoperative sagittal malalignment, the authors believe that surgical management should aim at a correction within the high normal kyphosis range of 40 – 50 degrees, consequently providing good results and, particularly in flexible adolescents and young adults, minimizing the necessity for an anterior release

Murray PM, Weinstein SL, Spratt KF ( 1993) The natural history and long-term follow-up

of Scheuermann kyphosis J Bone Joint Surg Am 75A:236–48

Sixty-seven patients who had a diagnosis of Scheuermann kyphosis and a mean angle of kyphosis of 71 degrees were evaluated after an average follow-up of 32 years The results were compared with those in a control group of 34 subjects who were matched for age and sex: The patients who had juvenile kyphosis had more intense back pain, jobs that tended

to have lower requirements for activity, less range of motion of extension of the trunk and

less-strong extension of the trunk, and different localization of the pain No significant

differences between the patients and the control subjects were demonstrated for level of

education, number of days absent from work because of low-back pain, extent that the

pain interfered with activities of daily living, presence of numbness in the lower

extremi-ties, self-consciousness, self-esteem, social limitations, use of medication for back pain,

or level of recreational activities

Poolman RW, Been HD, Ubags LH ( 2002) Clinical outcome and radiographic results

after operative treatment of Scheuermann’s disease Eur Spine J 11: 561–9

This paper is a prospective study to evaluate radiographic findings, patient satisfaction

and clinical outcome, and to report complications and instrumentation failure after

operative treatment of Scheuermann’s kyphosis using a combined anterior and

poste-rior spondylodesis Significant correction was maintained at 1 and 2 years follow-up but

recurrence of the deformity was observed at the final follow-up The late deterioration of

correction in the sagittal plane was mainly caused by removal of the posterior

instru-mentation, and occurred despite radiographs, bone scans and thorough intraoperative

explorations demonstrating solid fusions There was no significant correlation between

the radiographic outcome and the SRS score Therefore, the indication for surgery in

patients with Scheuermann’s disease can be questioned and surgery should be limited to

patients with kyphosis greater than 75 degrees in whom conservative treatment has

failed

Soo CL, Noble PC, Esses SI ( 2002) Scheuermann kyphosis: long-term follow-up Spine J

2:49–56

Sixty-three patients were evaluated a mean of 14 years after treatment (10 – 28 years)

using a specially designed questionnaire The patients had been treated using three

dif-ferent treatment modalities: exercise and observation, Milwaukee bracing, and surgical

fusion using the Harrington compression system At the time of follow-up evaluation,

there were no differences in marital status, general health, education level, work status,

degree of pain and functional capacity between the various curve types, treatment

modality and degree of curve Patients treated by bracing or surgery did have improved

self-image Patients with kyphotic curves exceeding 70 degrees at follow-up had an

infe-rior functional result

Stagnara P, De Mauroy JC, Dran G, Gonon GP, Costanzo G, Dimnet J, Pasquet A ( 1982)

Reciprocal angulation of vertebral bodies in a sagittal plane: Approach to references for

the evaluation of kyphosis and lordosis Spine 7:335–342

This report establishes a table of references for kyphosis and lordosis in a sample of

100 healthy adults (43 females, 57 males, age 20 – 29 years) from France Segmental

measurements were carried out from standing lateral radiographs of the whole spine

Mean thoracic kyphosis was 37 degrees (range 7 – 63); mean lumbar lordosis was

50 degrees (range 32 – 84) The majority of individuals had a thoracic kyphosis of

between 30 and 50 degrees There was a correlation between sacral slope and lumbar

lordosis and thoracic kyphosis The considerable variability is stressed As the

distri-bution was found to be irregular, the authors consider it unreasonable to speak of

nor-mal kyphotic or lordotic curves They state that average values are only indicative not

normative

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