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`NUVASIVE 1017
`NuVasive, Inc. v. Warsaw Orthopedic, Inc.
`IPR2013-00208
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`OBSERVATIONS ON THE MANAGEMENT OF FAILED
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`SPINAL OPERATIONS
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`H. V. Cnocx, MELBOURNE, AUSTRALIA
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`From St Vincent’s Hospital, Melbourne
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`A system is presented for the analysis of failure after spinal operations: 1) outright failure; 2) temporary
`relief; 3) failure in spondylolisthesis; and 4) infections. With this system it is possible to trace the causes of
`failure and to correct some of them. When they are used as a guide before operation, the recommendations
`made should help to prevent many failures.
`
` Patients with serious spinal problems are often given
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`re warnings about surgical operations, not only from
`non-medical sources but even from some specialist sur-
`geonS. In a review article on intervertebral disc prolapse,
`._ '3'Tay101‘ and Akeson (1971) wrote: “Surgery has long since
`_-bcen shown to be far from the ideal solution”. Reviews
`of various types of spinal operations usually refer to a
`3' hard core of up to 20 per cent of poor results.
`In some
`_:"s'pecific instances such as Staufl'er and Coventry’s (1972)
`i.--;?=review of anterior lumbar fusion operations carried out
`-._;_a_t {the Mayo Clinic, results may be so poor that any
`.; [useful role for a particular operation is placed in serious
`
`- Against such a background, problems in the manage-
`E'I- ':Heat of failed spinal operations present a sobering spec-
`-'_tac1e. The aim of this paper is to present a rational
`-'j:3_"=approach to them and so to sound a note of confidence
`“L and hope which may help to dispel the gloom that so
`"-3-;often confounds the unfortunate patient and depresses
`his physician. This can be a rewarding field of surgery
`because many patients will be found to have readily
`' correctable lesions even after prolonged periods of
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`THE PSYCHOLOGY OF FAILURES
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`? gleith rare exceptions psychological disturbances Will be
`,_E__fcu1_1d in these patients. The surgeon should remember
`that chronic pain adversely affects a patient’s mental state,
`gender-lug him in varying degrees depressed, anxious and
`aggressive—features of behaviour which are reversible if
`"-'_:tii_e. cause of pain can be discovered and corrected. Drug
`'r.‘-‘—--ac_ldiction sometimes causes added difliculties, though it
`‘- Fla)"not contra-indicate further operation. A few patients
`~-._;".':‘i11’_insist on operation after operation, often seeking
`[-.'many opinions and submitting to multiple procedures at
`_e hands of different surgeons. They form a rare and
`tragic group for whom further operation may only lead
`.' to..suicide, though many survive to end1n financial ruin.
`Psychological assessment along the lines suggested
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`in the present context such testing assumes even greater
`importance. Formal psychiatric treatment may also be
`required.
`The analysis of individual cases of failed spinal
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`FIG.1
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`Antero-posterior tomograph of the lower lumbar
`spine in a patient aged 37 years, said to have under-
`gone laminectomy for removal of left lumbo-sacral
`disc prolapse. Part of the upper margin of the .
`lamina of the fourth lumbar vertebra has been
`removed, so that the space between the third and
`fourth vertebrae was probably explored. The out-
`line of the myodil shows that there is bilateral
`stenosis of root canals at the L.4-5 level.
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`operations may be facilitated by using the following
`classification: 1) Outright failure: This group comprises
`patients who show no improvement or who become
`worse after the first operation. 2) Temporary relief: These
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`H. V. CROCK
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`3) Failures in spondylolisthesis: These patients are con-
`sidered separately because of special features of the patho-
`logical anatomy in spondylolisthesis. 4) Infection.
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`clinical examination and by myelography. However, in
`cases of failure the possibility of such lesions should be
`considered.
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`OUTRIGHT FAILURE
`
`Error in the diagnosis of the spinal condition and technical
`error
`
`Failure is usually related to wrong diagnosis. Some pain
`and discomfort are to be expected after any spinal opera-
`Pain protracted over weeks may follow some
`operations in which adherent root sleeves have been
`tediously separated from disc tissue, yet a successful
`outcome can be predicted. Such special circumstances
`excluded, patients in this group can usually be identified
`soon after operation. They complain of pain which is
`more severe than is normally to be expected. Those with
`infections will have elevated temperatures and altered
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`The questions to be determined are simply these:
`Is the failure due to an unrecognised condition? Is it
`due to wrong diagnosis of the spinal lesion? Or finally,
`is it due to technical failure ?
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`Unrecognised conditions
`Investigations should begin as soon as possible, but
`several months may elapse before the diagnosis can be
`established. For example, a carcinoma involving the
`apex of the lung may be the cause of neck pain and
`brachial neuralgia persisting after anterior cervical fusion.
`Operation for lumbar spondylolisthesis may fail because
`the true cause of pain is a secondary prostatic carcinoma.
`Rarely, infection after operation may be caused by
`tuberculosis or gonorrhoea.
`Primary tumours in the spinal canal are relatively
`rare. They are usually diagnosed before operation by
`
`Three questions must be answered: 1) What was the
`primary diagnosis ? 2) What were the operative findings?
`and 3) What was the nature of the operation?
`Failure after operation for disc prolapse—Persistence of
`severe pain is unusual if the diagnosis of disc prolapse
`has been confirmed at operation.
`If a considerable
`amount of fragmented and desiccated disc material has
`been removed, it is likely that a further fragment has
`been displaced beneath the root sleeve after operation,
`or that a migrating sequestrated fragment has not been
`removed.
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`If a pre-operative diagnosis of disc prolapse was made
`but no disc prolapse was found at the time of operation,
`it is likely that the intervertebral space at the wrong level
`has been explored (Fig. 1).
`Most failures occur when no frank prolapse is found.
`The diagnosis of internal disruption of the disc should
`have been established by discography before operation.
`Failure after operation for internal disruption of the disc——
`If this diagnosis has been established by discography and
`disc excision and interbody fusion have been done, early
`failure may indicate that the operation was at the wrong
`level. In the neck particularly, levels should be identified
`by radiographs taken during operation. The injection of
`methylene blue at the time of discography is an unreliable
`method of identifying the level of an affected disc. Even
`in the lumbar spine, levels may be wrongly identified,
`especially if there are anomalies such as sacralisation.
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`OBSERVATIONS ON THE MANAGEMENT OF FAILED SPINAL OPERATIONS
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`“FIG. 6 I
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`FIG. 7
`Degenerative change thirty years after removal of intervertebral disc at L.4—5 level in a patient now aged 61 years. Note the
`interlaminar calcification. Figure 8 shows the extent of laminectomy done for decompression.
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`FIG. 8
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`FlG. 11
`FIG. 10
`FIG. 9
`Chemical discitis in a woman aged 32. Figure 9—Discograph shows posterior disruption at the level L.2-3, with
`normal disc at level L.3—4. The patient killed herself six months after anterior intervertebral fusion. Figure 10—
`Photograph of thin sagittal section of the lumbar spine taken at necropsy. At the level L.2—3 union of the graft
`is incomplete. There is erosion of the lower end-plate of the body of the third vertebra with reactive changes in
`an excavated area of the body, from chemical discitis. Flgure ll—Section of the same specimen after arterial
`injection. Note the disc remnants infiltrating the grafted area at L.2—3 in the centre of the picture. On the right
`tufted vessels abut against invading disc tissue. Centrally the graft is vascularised. Note the reactive changes
`around the lesion in the lower part of the third vertebra.
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`If there is any doubt about identification, radiological
`examination should be done before anaesthesia is
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`possibility that the symptoms are those of “claudicationf’
`of the cauda equina must be borne in mind. Under such
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`H. V. CROCK
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`disc spaces are well preserved, the pedicles are short and
`the laminae and facets are so oriented as to raise the
`suspicion of stenosis.
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`on, especially if a large volume of disc material was
`removed at the original operation, or by a fresh prolapsc
`at another level.
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`TEMPORARY RELIEF
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`Initial relief of pain after operation and periods of free-
`dom lasting weeks or months are followed by recurrence
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`Recurrent but contralateral sciatica occurs after
`asymmetrical settling of the vertebrae when several grams
`of disc material have been removed at the initial opera-
`tion. Radiographs show collapse of one side of the
`intervertebral space. Recurrence of pain is caused by a
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`FIG. 13
`Lateral radiographs of the cervical spine of a man aged 39 years.
`Figure 12—The condition nine months after anterior fusion for
`degenerative change. There is non-union. Figure 13—Six months
`after replacement of the graft union is established.
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`FIG. 15
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`Lateral tomographs of the upper lumbar spine of a man aged
`46 years. Figure l4—Three months after operation. A circular
`cancellous graft has been inserted transversely at the L.3—4 level.
`Figure lS—One year later. There is collapse of the graft and
`established non-union.
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`FIG. 17
`FIG. 16
`tomograph of the lumbo-sacral
`Figure l6—A lateral
`junction in a woman aged 32 years taken four months after
`interbody fusion showing graft incorporation with preserva-
`tion of disc height and intervertebral foramen dimensions.
`Figure l7—A lateral
`radiograph of the lumbo—sacral
`junction in a man aged 46 years taken eighteen months after
`interbody fusion. The graft has incorporated but secondary
`disc space collapse has occurred with resulting nerve root
`canal and intervertebral foramen stenosis.
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`
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`FIG. 18
`Method of cutting grafts from the anterior
`third of the iliac crest. The graft has
`“tooled” cancellous surfaces and stout
`cortical faces on either side.
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`fresh prolapse of disc material or by stenosis of the
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`OBSERVATIONS ON THE MANAGEMENT OF FAILED SPINAL OPERATIONS
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`generative changes (Figs. 6 to 8). There may be ectopic
`ossification or calcification in the remnants of ligamentum
`fiavum at the site of exploration.
`Another cause of late recurrence, often associated
`with secondary canal stenosis but contributing to the
`overall problem, is the presence of a meningocele caused
`by damage to the dural sac at operation.
`Failures after operation for internal disc disruption—If
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`plate and body in the area of the nucleus pulposus occurs
`on either side of the disc leading to gross narrowing of
`the intervertebral space. Histological examination of
`specimens removed at operation shows inflammatory
`changes with plasma cell infiltration. Cultures are sterile.
`Injection of steroid into the disc usually controls the pain
`and promotes healing.
`Non-union of grafts occurs in a few single-level
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`FIG. 19
`Lateral tomograph of the lumbo-sacral junction in a man
`aged 42 years, after intervertebral fusion with a plug of calf
`bone. Note the inadequately inserted graft. Fusion failed,
`but was later secured by a posterior operation.
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`
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`Figure 20—Lateral radiograph of the cervical spine of a woman
`aged 56 years showing sound'fusion between fourth, fifth and
`sixth vertebrae. Pain in the neck, occiput and upper lirnbs was
`not relieved by this operation.
`Figure 21—Antero-posterior
`tomograph of the neck of the same patient after extensive laminec-
`tomy. Symptoms were relieved by this operation.
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`FIG. 23
`FIG. 22
`Figure 22—L.ateral radiograph of the lower lumbar spine of a
`woman of 37 years with persistent pain in the back and lower limbs.
`Note the narrowing of the lumbo-sacral intervertebral space, with
`minimal osteophyte formation and marked sclerosis of the vertebral
`bodies. Figure 23—The antero-posterior radiograph shows the
`amount of bone removed at two previous operations.
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`Antero-posterior radiograph of the lower
`lumbar spine of a man Of 40 years after a
`two-level
`decompression
`larninectomy.
`The regular outlines of the lamina] rem-
`nants are shown. Contrast this appearance
`with that shown in Figure 23.
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`interbody fusion has been performed for this lesion, early
`recurrence of severe symptoms within two or three months
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`fusions (Figs. 12 and 13). Replacement of the anterior
`graft is easy in the case of the neck, but in the lumbar
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`H. V. CROCK
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`resorption (Figs. 14 and 15); secondly, even though union
`occurs, loss of disc height may follow settling of the graft
`into the vertebral bodies.
`Stenosis of the nerve root
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`canal follows and may cause recurrence of pain in both
`lower limbs (Figs. 16 and 17). Block or dowel grafts
`cut from the anterior half of the iliac crest (Fig. 18)
`provide grafts which are rapidly revascularised, usually
`maintain height and always resist infiltration by disc
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`Heterogenous grafts may fail to incorporate, par-
`ticularly if inadequately seated (Fig. 19).
`After successful
`interbody fusion there is often
`atrophy of the ligamentum flavum:
`in the neck this
`atrophic ligament tends to adhere to the dural sac and
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`After cervical spinal fusion at several levels, move-
`ment at the level above the fusion may be excessive and
`may lead to premature disc degeneration. Before this,
`the excessive movements may aggravate other continuing
`causes of persisting root irritation, such as canal stenosis
`or adhesion of the ligamentum flavum to the dural sac.
`If symptoms have persisted unchanged after fusion,
`laminectomy at several levels with excision of the atro-
`phic adherent ligamentum over the fused segment pro-
`duces relief (Figs. 20 and 21).
`Failure after operation for isolated disc resorption—This
`in which one lumbar disc space becomes
`narrowed to a height of three to four millimetres, may
`occur naturally with no inflammatory basis.
`It may
`develop after partial excision of a disc or after chymo-
`papain injections. Symptoms usually recur or persist
`after a second exploration of the disc space with hemi-
`laminectomy and removal of more disc material (Figs.
`22 and 23). Bilateral decompression of root sleeves is
`required. This involves excision of the inner and superior
`margins of the superior facet on the lower side of the
`together with the ligamentum flavum
`(Crock 1970). If two adjacent spaces require decompres-
`sion, then partial facetectomy and laminal arch excision
`are necessary, leaving a regular defect in the roof of the
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`spinal canal, bounded on each side by the smooth edges
`of the pars interarticularis of the lamina (Fig. 24).
`Failure after posterior
`spinal
`fusion—Pseudarthrosis,
`spondylolysis in the laminal arch above the fused seg.
`ment, and secondary stenosis of the spinal canal, are Well
`recognised causes of failure, but inaccurate placing of the
`graft so that a piece of it extends beyond the intended
`level (Figs. 25 and 26) can also cause recurrence of pain
`by acting as an irritant of the facet joint system at the
`mobile segment above the graft. Excision of the prolonga.
`tion together with bilateral nerve root canal decompres-
`sion at the mobile segment usually brings relief.
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`FAILURE AFTER OPERATION FOR
`SPONDYLOLISTHESIS
`
`The role of the laminal pseudarthroses as a cause of root
`irritation in spondylolisthesis was stressed by Gill and
`White (1963). Simple removal of the loose fragment of
`the lamina and inferior facet, even when combined with
`posterior spinal fusion, may fail to relieve the leg pain.
`The pseudarthroses are immediate posterior relations of
`the emerging root sleeves (Figs. 27 to 30). Each pseud-
`arthrosis has two faces, one on the laminal side, and one
`on the proximal portion of the pars interarticularis, which
`is continuous with the adjacent pedicle.
`In order to
`decompress the related root canal adequately, this proxi-
`mal face must be removed (Figs. 31 and 32).
`Other causes of failure after operation for spondy-
`lolisthesis may be unrecognised associated stenosis of the
`spinal canal, or a disc lesion at an adjacent level, or
`progressive vertebral slipping. Late failure may be due
`to prolapse of a disc at a level above that of the fusion.
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`INFECTION
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`Infection is usually eradicated if it is recognised early
`and treated by reopening of the wound, by free drainage,
`and by antibiotics. Under such circumstances the wound
`may be closed after seven to ten days.
`The management of chronic infection is more diffi-
`cult. In the case of infection after posterior fusion radical
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`OBSERVATIONS ON THE MANAGEMENT OF FAILED SPINAL OPERATIONS
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`199
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`excision of the graft and sinus tracks is essential. The
`exposed dural sac will become covered with granulation
`tissue in the course of several weeks.
`If appropriate
`antibiotics are given, secondary infection should not
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`not only on the state of union of grafts, but also on the
`extent of bone removal. Positive and negative contrast
`myelography, and radiculography, are important in the
`demonstration of deformity of the theca or root pouches.
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`FIG. 27
`Floating lamina removed from the spine of a
`woman aged 56 years. The pseudarthroscs
`are viewed in the coronal plane. Note the
`loose body on the right.
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`FIG. 31
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`FIG. 3 2
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`Antero-posterior and lateral radiographs of the lumbo—sacral area in a
`woman aged 42 years who underwent anterior fusion and later re-
`moval of the floating lamina for spondylolisthesis. Figure Ill—Note
`the clearly defined free margins of the pedicles of LS after excision of
`the floating lamina and the proximal portions of the pseudarthroses.
`Figure 32—Sound intervertebral fusion. Note the smooth margins
`of the pedicle.
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`FIG. 29
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`FIG. 30
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`The relationship of the larninal pseudarthroses to the nerve root and to the other vertebral elements.
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`occur, even in the presence of a small cerebro-spinal
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`IMPORTANT DIAGNOSTIC AIDS
`
`Tomography can provide extremely useful information,
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`Lumbar discography is important in cases of failed lami-
`nectomy for suspected disc lesions and in some cases of
`spondylolisthesis, to determine the exact level and extent
`of spinal fusion which may be required. Axial tomo-
`graphy may well be of great value in assessing stenosis
`of the spinal and root canals.
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`This work was supported in part by a grant from Mr A. D. McLean, to whom I express sincere thanks.
`REFERENCES
`
`Crock, H. V. (1970) A reappraisal of intervertebral disc lesions. Medical Journal of Australia, 1, 983—989.
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