THE POST-LAMINECTOMY SYNDROME ■ by M arge Steffen, Private Practitioner, Kempton Park INTRODUCTION The post-lam inectom y synd rom e is defined as a term encom ­ passing all persistent severe sym ptom s follow ing op eration on a lum bar d isc1. It is thought to be due b oth to instability o f the m otion segm ent and ad hesions in the spinal canal. Spangfort^ review ed the results of 2504 lam inectom ies, se­ lected for the study becau se they had clear-cut signs o f nerve root entrapm ent. H e found that com plete relief o f both leg and back pain post-operatively occurred in only 60% o f cases. Failure to relieve pain in these cases o f nerve root entrapm ent w as attributed to one or m ore o f the follow ing: • The exploration hav ing b een carried ou t at the w rong level • A second disc prolapse having b een overlooked • The nerve root continu in g to be com pressed by the posterior intervertebra 1 jo ints • Spinal stenosis cau sing pressure on the nerve root • Rarely, becau se o f an extraforam inal lateral disc herniation^. W ilkinson^ prefers the term "failed back synd rom e" because the synd rom e is n ot alw ays preceded by an incorrectly perform ed operative proced u re b u t can also occu r follow ing correctly per­ formed surgery. Should w e, therefore, look beyond surgery for other perpetu­ ating causes of the residual pain? W hy does pain continue post- operatively? Is this pain neurogenic or m u sculoskeletal? Can we treat this cond ition effectively? Theoretical assumptions A s far back as 1983 Travell and Sim ons suggested that m yo­ fascial trigger points w hich have becom e activated pre-opera- tively are likely to rem ain active post-operatively, and are there­ fore likely to continu e to cause pain long after the nerve root has been decom pressed satisfactorily. To test this assum ption 1 have assessed the presence o f trigger points and the patterns of pain pre- and post-operatively in patients treated in a surgical spinal unit. P re-operatively, trigger points produ cing pain w ere identi­ fied but d eactivation o f these trigger points did not have a lasting effect. Post-operatively the trigger points w ere found to be situ­ ated in the sam e d istribution and deactivation over several treat­ m ent sessions provided lasting relief o f pain. The pu rpose o f this article is not to discuss the research as such, but to exam ine theoretical assum ptions regarding the m echa­ nism s of pre- and post-operative pain w hich m ay explain the results o f the study. Pre-operative back pain The developm ent o f disc herniation at the level o f the lower lum bar segm ents is assum ed to set the pain process in operation. Altered segm ental function provokes protective spasm in the m uscles surrou nding the jo ints, resultin g in segm ental im balance locally. This results in com pen satory reaction and adaptation in other segm ents so that finally the w hole spinal system is reflexly involved in the activation o f trigger points*’. A cycle o f strain and resultant p ain is set up w hich m agnifies and reinforces this m echanism as the local pathology progresses. Second ary m uscle and fascial shortening occurs w hich is responsible for generalised m uscle stiffness and restriction o f jo in t m ovem ent and, in turn, ^SUMMARY ^ Pre-operative patterns of pain and altered function have been found to persist post-operatively following disc surgery. This article explores theoretical concepts which may provide a rationale for successful post-operative treat­ ment. V______________________________ J restrictive involvem ent of jo in t structures. It is this low back stiffness, in addition to pain, w hich causes the patient to develop abnorm al patterns o f posture and gait. Pre-operative leg pain Sim ultaneous with the m echanism s described above, en trap ­ ment of the em erging nerve root by the disc prolapse gives rise to radicular pain in segm ental distribution in the leg. The m uscles supplied by this nerve root respond by going into spasm . A s in the case of local b ack pain, prolonged spasm leads to shortening and to the developm ent o f trigger points w hich in turn generate their ow n patterns o f referred pain. Post-operative pain The two causes of the post-lam inectom y synd rom e have been stated to be m otion segm ent instability and the presence of ad he­ sions in the spinal canal. It is possible that m otion segm ent instability is not only due to expulsion or operative rem oval o f the intervertebra 1 disc, but also to im balances in the intrinsic m usculature due to the pre-opera- tive developm ent o f the cycle o f altered segm ental function as described above. This w ould explain the persistence of abnormal patterns o f posture and gait post-operatively. Adhesions are know n to develop in the operative area as a result of fibrous organisation of bleeding and exudate. These adhesions involve the dura and nerve roots by restricting their m ovem ent w ithin the spinal canal and the intervertebral foram ­ ina, leading to adverse neural tension. Such adhesions m ay also produce com pression o f the nerve root post-operatively, resulting in pain. It is striking that the som atic pattern o f d istribution dow n the leg post-operatively so closely m im ics that o f the original radicular pain. A dverse neural tension can also be generated by restrictions at mechanical interfaces occurring as a result o f the altered segm en­ tal function and subsequent m uscle spasm and m yofascial sh ort­ ening. Even m inimal pressure com prom ises the blood supply to the nerve and affects the function o f the nervi nervorum supp ly­ ing the nerve itself. Increasing pressure affects axonal flow and nerve conduction. Treatment considerations From the above it is apparent that the causes o f post-operative pain m ay be multiple, involving not only instability o f the m otion segm ent and adhesion form ation, but also the perpetuation of altered segm ental functions and trigger points activated pre-op­ eratively. Treatm ent has to be directed at all the involved struc­ tures - join t, m uscle, fascia and nerve - and experience has shown that better results are obtained if such treatm ent is instituted im m ediately post-operatively. The aim s o f treatm ent are to relieve back and leg pain and to restore m axim um function. Since shortening and stiffness m ay be SA J o u r n a l P h y s io th e r a p y , V o l 5 2 N o 1 F e b r u a r y 1996 P a g e 7 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) the m ajor cau ses o f p ost-lam inectom y pain, treatm ent m ust be d irected at releasing the stru ctures involved. Conservative measures D rugs, a corset and b ed -rest are appropriate in the early stages and are beneficial in restricting the inflam m atory process and thereby relieving im m ediate post-operative pain. The joints P assive intervertebral jo in t m obilisation aim s to m obilise ad­ herent stru ctures w ithin the central canal as well as in adjacent lateral canals. Specific techniques fo r the low er lum bar motion segm ents are directed initially at relieving pain, utilising sm all am plitude m ovem ents, and progress to deeper grad es to reach the end o f available range and treat stiffness. W here indicated, generalised and localised m obilising tech­ niques are applied to jo in ts at other levels o f the axial skeleton in order to treat restrictions w hich have resulted from com pensatory m echanism s. The soft tissues By releasing the restrictions in soft tissues surrounding the affected vertebral segm ents and locating and releasing the offend ­ ing trigger points in the leg, pain can be relieved. The resultant m uscle lengthening sp ontaneo u sly facilitates strengthening o f the w eakened m uscles and aids in restoring norm al segm ental func­ tion. A fter release o f trigger points, jo in t m obilisation and m yo­ fascial stretching techniqu es are used to restore norm al m obility. M u scle strengthening is directed tow ards stabilisation of the lum ­ b ar m otion segm ents in the norm al physiological lordosis by activation o f the intrinsic m usculature. F ollow ing surgery, neural m obilisation is o f particular im por­ tance in restoring spinal and limb m obility. R estriction o f neural m ovem ent occu rs n ot only in the spinal canal and ad jacent stru c­ tures, due to ad hesions, b u t also at the m echanical interfaces w ithin m uscles and ligam ents and at bony attachm ents due to the altered fu nction and restricted m ovem ent pre-operatively. M obi­ lisation o f the nervous system plays an im portant part in influ­ encing the tension and m ovem ent o f neural stru ctu res, thus im ­ proving vascu lar d ynam ics, axonal transp ort system s and the m echanics o f neural fibres and nervous conn ective tissue. Im ­ proved blood supp ly to the nerve itself m ay play an im portant part in restoring norm al nerve cond u ction and relieving pain. Compensatory mechanisms C om pensatory postural m echanism s m ay n ot in them selves be sym ptom atic, bu t w ill prevent norm al alignm ent and fu nction of the lum bar spine, leading to fau lty posture, u neven w eight distri­ bution, altered patterns o f m ovem ent and gait and secondary decreased m obility o f the related so ft tissue structures. These com pen satory m echanism s m ay persist after rem oval o f the o rigi­ nal cause and, unless tackled, w ill in them selves perp etu ate pain. Successful long term results depend up on effective postural re­ education. Conclusion The successful m anagem ent of p o st-lam in ectom y sy nd rom e is a challenge to the physiotherapist, b oth in h er evaluation and d ifferentiation o f the un derlying cau ses and in the effective treat­ m ent o f the involved structures. O n ly early and intensive treat­ m ent o f all stru ctures involved w ill achieve a successful result. References 1. K ram er, Ju rgen. Intervertebral D isc D iseases. In: L u m ba r S yndrom e. 2nd edition. T hiem e M ed ical P u blish ers, Inc., N ew York. 2. Sp an g fo rt E V. T he Lu m b ar D isc H erniatio n. A C o m p u ter-aid ed A n a ly ­ sis o f 250 4 O p era tio n s. A cta O rth op aed ica S can d in av ica Supplem ent 1972;142:1-95. 3. N elson M A. Su rg ery o f the Sp ine. In: Jayson M I V (ed) The L u m ba r Spine a n d B ack Pain. P itm an , Lond on 2nd E d n 1980:477. 4. W ilkin son HA. The F ailed B ack Syndrom e. H arp er & R ow , N ew Y o rk 1983. 5. T ravell J G, Sim on s D G. M yo fascial P ain and D y sfu nctio n . The Trigger Point M anual. W illiam & W ilk in s, B altim o re 1 9 8 3 a ;1 0 5 -1 0 9 :1 9 8 3 b ;8 4 5 : 1983c;884: 1983d;837. 6. Jand a V. M u scles, C en tral N ervou s R egu lation and B ack P ro b le m s. In: K orr IM : The N eu robiologic M echan ism s in M an ip id ativ e Therapy. Plenum P ress, N ew Y o rk 1978. THE SMITH AND NEPHEW EDUCATIONAL TRUST S m it h a n d N e p h e w a n n u a ll y d o n a t e a T r a v e l B u r s a r y to m e m b e r s o f th e S A S P in r e c o g n it io n o f th e lo n g a s s o c ia tio n o f th e C o m p a n y w ith th e p h y s i o t h e r a p y p r o fe s s io n . 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T h e S o u th A f r ic a n S o c ie t y o f P h y s io t h e r a p y is v e r y g r a te f u l fo r th is g e n e r o u s g e s t u r e b y S m it h a n d N e p h e w , w h ic h w ill b e o f p a r t ic u la r v a lu e in th e s e d if f ic u lt e c o n o m ic tim e s . B la d s y 8 F e b r u a r ie 1996 SA T y d s k rif F is io te r a p ie , D e e l 5 2 N o 1 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. )