An investigation into the effectiveness of collagenase for the percutaneous discolysis of thoracolumbar intervertebral discs in the dog : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University

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AN INVESTIGATION INTO THE

EFFECTIVENESS OF COLLAGENASE FOR THE PERCUTANEOUS DISCOLYSIS OF

THORACOLUMBAR INTERVERTEBRAL DISCS IN THE DOG

A thesis presented in partial fulfilment of the requirements for the degree of Master Of Veterinary Science

at Massey University

JONATHAN PETER BRA V

1993

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• • • 11

Abstract

T his investigation compared the effectiveness of chemonucleolysis with 500 units of collagenase, to lateral fenestration of the thoracolumbar intervertebral discs of the non- chondrodystrophoid dog. Effectiveness was based on the amount of nuclear material removed from the disc and the associated modifications to intervertebral disc structure, as determined by histological examination. The object was to determine whether the percutaneous injection of collagenase enzyme could be an alternative to fenestration as a prophylaxis against herniation of a degenerate intervertebral disc.

Eight one year old, non-chondrodystrophoid mongrel dogs were used in the experiment. Apart from two dogs which remained untreated, the remaining six dogs were from two litters which had been sired by the same animal. Two of these dogs had six intervertebral discs (Tl0/11

to

L2/3) injected with 500 units of collagnease VIIs delivered percutaneously. Another two dogs had their equivalent discs surgical! y fenestrated by the lateral approach as described by Flo and Brinker. The remaining two dogs were subjected

to

a placebo injection of physiological saline.

The animals were examined clinically, neurologically and radiologically before treatment and at regular intervals following treatment. Six months following treatment, the dogs were euthanased.

The resul rs showed that collagenase caused almost complete removal of normal nuclear material from within the disc. The centre of the disc was replaced by a variable combination of fibrocartilage and hyaline cartilage, which appeared

to

develop from the collapsed inner lamellae of the annulus fibrosus. Complications were recorded in only one dog, who suffered a transient hind limb paralysis in the two days immediately following injection. A massive dorsal extrusion of nuclear material was observed in one disc at post-mortem in this dog and was believed to be the cause of the paralysis. The dog recovered without treatment and remained normal on clinical, neurological and radiological examination six months after injection. The annulus fibrosus, dorsal and ventral longitudinal ligaments remained intact in all other dogs.

Fenestration was found

to

cause a variable disruption

to

the normal architecture of the nucleus

pulposus. In most discs, cellular aggregations from the normal nucleus pulposus were

undergoing a transformation to fibrocartilage. These cell groups were separated by an increased

amount of amorphous matrix material which stained moderately with alcian blue. In the

remaining discs (3/12), an increased fibrosus of the nucleus pulposus was seen, but no other

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• • • Ill

disruption

^to

the normal arch itectu re was recorded. No complications occurred in these dogs.

The injection of the discs with physiological saline caused remarkably similar hiscologica l effects

to

the di sc as did fenestrati on.

The investigators concluded that collagenase appeared

to

be an attractive alternative

to

fenestration for t he prophylaxis of intervertebral disc herniation, on the basis of its com pleteness

of removal of nucl ea r ti ssue, and its simplicity, cheapness, non-in vas iveness and the lack of

mediu m and shore t erm complications. Since intervercebral di sc protrusions occu r more

commonly in chondrodystrophoid breeds of dog, the effe ct of col lagenase sh ou ld be studied in

degenerate disc of these breeds before it can be recomm ended for clinical use.

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• • • IV

Acknowledgements

I would like to thank my supervisors for their work in the preparation of this thesis: Hilary Burbidge for her constant support, guidance and perpetual good humour; Brian Goulden for his desire for excellence, and his clear guidance and thinking; Elwyn Firth and Keith Thompson for their positive com me ms and criticims. I would also like to thank Andy Bray for his assistance with the layout design of this thesis.

The collagenase used in this experiment was supplied by Sigma laboratories, and their support

is acknowledged.

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TABLE OF CONTENTS ^{• • • V}

TABLE OF CONTENTS

Aostra-ct

Acknowledgeme_:nc:t_cs _ _ _ _ _ Table of cOntents

List of illustr81:ions

SECTION 1.0 INTERVERTEBRAc Disc D1sEASE: AN INTRODUCTION

~1.-'1-~A~N~INTRODU-=C-'T~IO=--c:N _ _ _ _ _ _ _ _ _ ______ _ ( i)

( i:) (ir:) (ii)

B,-ud In.cider.a

- - - - - - - - - - -

Sex lnc:dmce

_ _ c_S~iU...'.cL,f in1,,,r,!1,e,mnt u,_it/_}_ inter,,'e:_!e~<?_l di.1c dis&:Jse _ Onset of clin£cril signs

-- - - -

- - - - - - - · - - 1.3 TREATMENT OF INTERVERTEBRAL DISC DISEASE

j' ~- /

1.3.2

Cc,,;.ien,;::'ve _1r,.;.na1,=r.t S:.rgical '!',..1n~f[:1'2n: __ _

SECTION 2.0 ANATOMY

2.1 - INTROD-UCTION

2.2 STRUCTURE OF THE VERTEBRA 2.2.1

222

2. 2.3 The ,uur,1! arch

---- - - - -

_______ 2.?_._4 ____ lirl~u_i_.:;,._(a:et pmtJ

_ _ __c2c...2.5 Tranwene roce.Js _ _ _ _ _ _ _ _ _ _ _ ---'2C...L2_. 6 _ _ _ I?oryal .,pinou_1 prca.ss

2.3 LIGAMENTS OF THE VERTEBRAL COLUMN _ _ ___c2:::."-3...'.l _ _ lntrodJ.ction

_ __c2c..3c..-~2 _ _ --=L.,m~,g /iga~tJ of 1ht Vertebral Column _..:2.cc3:::-,_3 _ _ _:S:::he="...cL:::'-"ga=~t_1 of the Ver-tebral Column

- - - · - - - -

2.4 MffSCULATURE OF THE-VERTE_B_R_A_L_C_O_L_U_M_N~---

- - - ~ - - - - - - -

2.5 THESPfNAt CORD

---,

ii

V X

2 2 3 4 4 5

8

12 12 12

n

i3 14 15 15

16 16 16 I -

18

18 22

23

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• • •

2.7

3.1 3.2

3.3

3.4 3.5

4.1 4.2

4.3

4.4

4.5

Vl TABLE OF CONTENTS

2 5. 1 Menin es 23

2 5.2 Spinal cord 24

(i) Sensory (ascending) tracts 26

(ii) Motor (descending tracts) 28

2.5.3 Blood supply to the Spinal cord 29

THE ANATOMY OF TH-~E~l-1c-N=T=E~RV~ER=T=E=B~R~A~L~D~,s~c~---'3:....:.2

2. 7. 1 Introduction 32

2.7.2 Grass Anatomy of the lntuvertebral Disc 33

273 Microscopic anatomy of the lntervertebral Disc 35

2 7.4 Molecular framework of the disc 40

INTRODUCTION 48

THE VERTEBRAL COLUMN AS A HORIZONTAL BEAM 48

3 2.1 The Bridge Theory 48

3 2.2 Theoretical Con.ride1'atiom 49

THE VERTEBRAL COLUMN AS A FLEXIBLE BEAM 51

331 The Bow-and-String theory 51

332 Experimental models 52

_M_O_T_IO_N_O_F_A_N_I_M_A_L_S_(_R_O_LE_O_F_T_H_E_V_E_R_T_E_B_RA_L_C_O_L_U_M_N_) _ _ _ _ _ _ _ _ _ 53

BIO MECHANICS OF THE INTERVERTEBRAL DISC 58

SECTION

4.0

DEGENERATION OF THE lNTERVERTBRAL Oise

INTRODUCTION 62

DEGENERATIVE CHANGES IN THE NON-CHONDRODYSTROPHOID BREEDS 63

4 2. l Grass chart es 63

42.2 Microscopic changes in the nucleus pulposus 64

423. U ltrastr11ctural changes 65

DISC DEGENERATION IN THE CHONDRODYSTROPHOID BREEDS 67

4 3.1 Grass changes 67

43.2 M icrascopic changes in the Nucleus PulpoJuJ 70

43.3 Biochemical changes 70

CHANGES IN THtANNULUS FIBROSUS WITH DISC DEGENERATION

74

4.4.1 The non-chondrodystrophoid dog 74

4.4.2 The chondrodystrophoid dog 76

THE PATHOPHYSIOLOGY OF DISC DEGENERATION 76

4 5.1 Annular Tears 78

4 5.2 Cellular influence on degeneration 80

4.5 3 Effects of Degeneration on Biomechanical Function 81

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TABLE OF CONTENTS • • • vi.i

________ 1 .. J .. 4_

l'.'JJtr-iticrna_l_!/f~s_?!}_ deg_er:eraticrn

_ _ _ _ (iJ D~ger._eration_of the Cartilagin_ous End Plate· S3

(ii) Fibrmis of the friten.,er::.,b,=al:_Ic:):ci,

0

c, _________________________ _

4.6 SUMMARY: INT_E,R_v§__RI_EBR..,.Ac-L'-'D=-'1-::S_,,C_.D:.clS::cE-:A..,.S~E,____________ _ ____ 8_4

SECTION

5.0

FENESTRATION

s.1 · -1NTR001JCTION - - - - - - - 88

- - - - _ _ _ _ 8.S

5.2 FENESTRAI!QN_A~,\_:r_~EATMEN.,_T.,__ __________ _ --- 5.4 . FENESTRATION AS A PROPHYLACTIC - - - -

- - - ----- - - - - - - ----^{- -}---^{- - -}---^{- - - -}

5.5

6.1 54 I _'5.4.2

f!ec~r-e~o of

p~,

p,..ofa_p1e _ - - - __ - - - _ _ - - - _ [j/ic.x!.. cf Fmesfr,1::on

-~4_) ___ __ __ _!:_!o.:_fd:~z_ _______ ___ _ - - - -- - - - -- - - - - - - SUMMARY

SECTION

6.0

CHEMONUC!.EOLYSIS

·1NTRODUCTION ..

-- _!}_~_Ll --- - -- Pharm._~£._ll)f;)

__ 6.2.2 ______ Tox1dl) of Chymot,,~1_~m _______ ________________ _ 6.2 3 -~i~'!_i_;:_.!.!__Y_5_JJ_{ts_.}!'_?_~~--Ch)"''f'"f':!:_1!_ ____ _

6.2.4

6.3 -coCT.AGENt>.SE _-_--- - - - - --- - - · - - - - -- - - ------^{- - - - -} ^-

6 3 I 6 3.2

_!/JD::~/

Co!lagnum _!!!_

0~

mten,ertebr'!_i d,_(C _______________ _

- - - -

--- 6.3.3 _ _ __ C/;_n_ic.:1/ U.H ofC_dl.a5er.,,_m

91 92

96

98 98

:01

103

6.4 CONCLUSIONS - - - --· -- - ~ - - - - · - ·-- 106

7.0

CONci.USIONSANDRESEARCH O B J E C T I V E S " - - - -109

SECTION

8.0

MATERIALS AND METHOD

8.2 EXPERIMENTAL PROCEDURE - - - - 8.2.J Anan1he1ia

---~?.,2_____ R"'!}i~graphic a.ue.mnen! ____________ _ 8.2.3 Injection u~hnique_

---~j_ ____ _!_'!l_Pflion ofcollae,.e!!_a!_l_ - · _ __cBcc'cc"·.c.5 _____ lnjution of Jc.lme _ _ _ _

8.2.6 ____ Surgical fenestration - - - - - - - -

- - - - - - -- - - -

. - . . 112 - - - -

- - - - · - - -- - - - 113

- - - I 1 3

- - - -- - - -

l] 3 ll 3 1 l 5 1 ](, JJ6

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...

^\'111 ^TABLEOF CONTENTS

8.3 POST-OPERATIVE EVALUATIOccN-'--- 117

- - - -- - - -

8.3. I ln vivo examinalions ll7

8.3.2 __ ____!_011-mortem analysis

- - - - -

ll 7

_ _ _ B~-~3~3~ _ _ !~'"~'-'~I,~gic~p!f,a!_~l_i'~"---'-' 1_7

8.3.4 l-listologica! ar.al)si..1 I 18

SECTIOi'<

9.0

RESULTS

9.1 -- ~RE-OPERATIVE'£VALUATIOl\i _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 126

~9=.2'----~E=X~P~E=R~l~M~E~N~T-~A~L'-P~R~O~C~E=D'-U=R=ES=-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 126

9.2. l Anaesthesia

9.2.2 Pre-Dperative r-adiographic a.H!"'..!_"'!_eri_t __

9.2.~3 _ _ _ l~nJ,!£1ion techn_i~q•_< _ _ _ _ _ _ _ _ _ _ _ 9.2.4 lnl«rion of col!ager.au

9 2.5 Injection cf saline ____ _ _ J,2_y __ Surgfraifenesfratfr_.n _ _ _ _ _ _ 9

.3--.

'post::-oj,ERATIVEEV ALUATIONS--

9.3.J ^/,1i-iw exammatior..s

- -- - - -

9.3 2 Post-mortem examina:ior.

- - - -

SECTIOO

10.0

DISCUSSION

10. 1-- DlSCUSSION ^--- ---- - - - - - 10:2-E°XP(RIMENTAL CRITICISMS

_ _ _ 126 126 I 26 ]26 ]26 _ _ _ 127

127

--- ---- - - - ~ 1 2 7

162 ---- - - -

___

^,,

__

^---167 10.3 CONCLUSIONS

SECTION A APPENO!X A A 1

.o

DlAGNOSISOF INTERVERTEBRAt: DISC DISEASr;

- - - -- - - - A 1. 1 NEUR6iOGICAL EXAMINATION _____ _

_ _ _ ,_'l~l_J._I _ _ G_-,.,_,,_a~I gait and___!__!__,rn_eth _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

A 1.1.2 MotortU/ilits _,,

_____________________ _

i) Fore.limb reflexeJ:

169

172 172 172 173 174 ii) Hindlimb ,e7exw

_ _ _ _ _ iiij Other refftxes: _ _______ _

- - - · - ----'-1~7 5 176

_ _ _ ,'1_1_. _1~3 _ _ Sm,c,ry d,fi_o_1; _ _ _ _ _ _ _ _ _ ______ _ 177

A 1.2-RADIOLOGiCAL

EXAMINATION . - - - · - - - ____________ 17_8

A. J.2,J A I.2.2

Plain radiographs Contrast radiography

(i) Cervical p11n.t11re (cisterna magna) (iij Lumba, p1m.cr11re

lnterfrretalion of the myelogram

178 179 180

!81 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 18}

182 (iii) Special imaging

- - - ~ ~ - - ~ ~ - - - --- - - -

A 1.3 tEREBRbSPINAL FLUID EXAMINATION---·---- 182

______

^,,^___^,___________ _

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TABLE OF CONTENTS ^{• • •} ^lX

A 2.0 TREATMENT OF INTERVERTEBRAL DISC DISEASE 183

A 2.0. J /n1roduc1ion 183

A 2.1 REVIEW OF SPINAL CORD INJURY ₁₈₄

A 2. 1.1 Direcl Morphological changes I 4

A 2.1.2 Vascular changes 184

A 2. 1.3 Biochemical and Melabolic changes 185

A 2.2 NON-SURGICAL (CONSERVATIVE) MANAGEMENT 186

2.2.1 Pharmacological agenls 187

2.2.2 1\¹^tJrJⁱⁿ ^care 188

A 2.4 SURGICAL MANAGEMENT 190

2.4. I Decompression (lamineclomy) 190

81BUOGRAPHV

B 192

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• • •

X TABLE OF CONTENTS

LIST OF ILLUSTRATIONS

SECTION1.0

Figure l. 1: The relative breed incidence of interoertebral disc disease in the dog 2

Figu.-e 1.2. Number of herniations recorded at each thoracolumbar intervertebra! space in the dog. 3

Figure 1.3: Photograph of a massive Type I disc herniation in a 5 year old Beagle. 5

Figure 1.4. Seven haematomyelia in the spinal cord of a 5 year old corgi following an acute disc herniation. 6

Figure 1.5: Photograph of a severe Type II lesion in a 9 year old Border Col/ie. 7

SECTION

2.0

Figure 2. 1: The axial skeleton of the dog shltwing the individual set:tions. 12

Figure 2.2: Structure of the fifth lumbar vertebrae, caudal Lateral aspet:t 13

Figure 2.2a: The vertebra! body 13

Figure 2.2b: The neural arch. 14

Figure 2.2c: The articular facets. 14

Figure 2.2d: The transverse prrx:esses. 15

Figure 2.3: The anticlinal vertebra. 16

Figure 2 4: The ligaments of the vertebral column. 17

Figu.-e 2.5: The superficial epaxial muscules of the dog 19

Figure 2.6: The deep epaxial muscles of the dog. 20

Figure 2.7: The hypaxial muscles of the dog 23

Figure 2.8: A cross-set:tion of the spinal cord showing the individual meningeal coats and related structures. 24 Figure 2.9: Cross-set:tion of the .1pinal cord showing the relative positions of the sertSO') and motor tracts. 27

Figure 2. IO: Thoracic and Lumbar vertebral veins, right lateral a.,pect. 30

Figure 2.1 l: The lnter,utebral Disc 32

Figure 2.12: Scanning elet:tron micrograph of the annulus fibrasus. 3 5

Figure 2.13: Photomicrograph of the normal annulus fibrosus, showing the junction between the lamellae and the cartilaginous

end plate (CEP). 36

Figure 2.14: Ekctron micrograph of a cell from the nucleus pulposus of a normal, human intervertebral disc. 38

Figure 2.15: Collagen content of the intervertebral disc 42

Figure 2. 16: Drawing of the proteoglycan mrx:et:ule, and its association with collagen 43

SECTION

3.0

Figure 3. I: The 'bridge theory'. 49

Figure 3.2: Bending moments alang the vertebral column 50

Figure 3.3: A beam, supported at one end only by being built into a wall, is given additional support by a stret:khed cord. 52

Figure 3.4: The thoracolumba,- spine of the Ungulates (A: horse; B: Bison). 54

Figure 3.5: Phylogenetic elrmgation of the distal end of the mammalian limb. 54

Figure 3.6: Two different phases of the leaping-gallop (cat, dog) and the horse-gallop (deer, horse). 55

Figure 3.7: The gallop of the cheetah. 56

Figure 3.8: Site of disc herniation in the human. 57

Figure 3.9: Compressive loading of the intervertebral disc. 59

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TABLE OF CONTENTS • • • xi

SECToo 4.0

_F~,g~•-~_4_. _1 _ _ _ _ _ D_egene,alion ~,f the nrm-chO'l'ldrodyt,-ophoid diin

~-i&}!!!.__4.2: Gl);:u~---;;,-i~--;giycam --;;;;hin the non-chrmdr~d}o:~Phoiin1,.deus pulosus u,·ith in;,.easing age

~ju~

4.3:

Deger.erai1·;;-o/ihe

chor.dr_~)sl,-ophoid dim. - --- ·

Figure 4.4: Thl di.Jtributior. of di.Jc calri/icathm and dm p,otNJ.5i01'1.J along ihe 1.e-;;g,h of the verte!wal column

~~---

Figure 4. 5 · The

imiJm;e

of diH hemwtionJ about the 'high-motion1 diapMagmatic rtgior..

---=--: __ _

~~1ure 4.6· Glycosaminoglyam u-ithin the chondrod)strophotJ nucltus pu/osus with in.:rea:,i,:g age -; J

t

^igu!e^{4~-~ __} ^Aschem,;;:fr-~/J;~r.tat10n of tbe development of disc degm·;;..;;:j;;-f;/h(

rum---ck,;,;J,.fd;-,.-,,-,;-,h~. ,-,a~'~d~,-,t-. - - - - :

2 (:_Jguf't_ 4. 8~- A ;chf:1714t;c npre.sMJ.tarion of the devet~---;;;,;n~f di.r~----:Jegeneration in the cho~rod_,.,;/rophoid disc

Fig:.re

4.9·

Representation u,( ty/Ji--;;;i f)/JI! land type

II

interveriebr~l

div:-h;;n,/;.!i;;~~

_F~ig~u_,_,_4_. _1_0_• __ -_· _·_1_⁰h_;_·~_i_t..,_1 , gen co~~e:}~f !he mdeus pulposli.J -~/both-cho_rz!!_~o._!_;('_~~p_hi: ar.:f 11011...:·ho-r.d~_}-;i,q;f;i~-d_l__!__cT-

!_igure _1}__1: The 'Jeff-he.a/mg' h.'.l_K_:f_~~_i5.:_ ____ _ _

SECTK)N 8.0

F:p,;--;-s ·e__ ____ - Pret--;;,_-;;;:;;----;-;;-~j-(ig.:.ti_o_'!_ ~/ the

in;;ai~

;;-;;;.~-ql<e

i_r: ca._i.3~-;-

!:__jgure 8~-~- ln;ecti_on uJmqut _______ _ _ _ ______________ _

SECTIOt< 9.0

0rure ') -

1\'o,.,,;;;1~~~leu;·;~i."ipcj1•.S

!_ig;m ]_ __ 2 _____ :

0otLJ_;n:.S~- fn,;e.·kd_d1~jl_

F ir.im ) 3 fm~_Jra!e..•' and S.:Jfiru: _:__:i_;ectcd d:r_c, I 1) _

0f~

⁹⁴ FeneJ/rated and Saline m;e.:ted D1_i.J !1i_!

I:-!_f,_k_"!._9) _ __________ D!_!:__;_;~~ L~r,i11,d:,;_1) f:f,F!n~-- __ --- --- F:;si,1..-t 9 6 \-'er.Ira! SJ1cr./rh:iJ D£form;.n3

[!}0

9-~---- ---~T_!~be.~u:C~--of_!}_x__~~i£i _ _______ ---~---

J l4

II 5

j'<Ji

154

1 SB I 5 R