Spinal adhesive arachnoiditis

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Spinal Adhesive Arachnoiditis R.A . Dolan, B .A., M .D .C.M., F .R.C.S.(C) Hamilton Hospitals, McMaster University Medical Centre, Hamilton, Ontario, Canada

Dolan RA . Spinal adhesive arachnoiditis . Surg Neural 1 1993 ;39 :479-84 . Forty-one cases of spinal adhesive arachnoiditis ate presented . The key points are, first, that lumbar disc lesions, their investigations and surgical treatment and the use of nonabsorbable contrast materials are the most common etiological factors and, secondly, that operation is the best treatment . It is our contention that the majority of patients so treated do experience some improvement in what otherwise can be an unbearable amount of pain and disability . The use of adsorbable, nonirritative contrast materials such as Iohexol Parenteral will result in a marked reduction in the frequency of occurrence of arachnoiditis . Lumbar disc ; Contrast material ; Fibrous tissue ; Operation ; lohexol Parenteral KEY WORDS :

Forty-one patients comprise the group of cases of spinal adhesive arachnoiditis to be analyzed . It is hoped that an examination of this series will serve to illustrate the etiology, clinical course, methods of treatment, and follow-up management of a difficult problem. There are two courses of action to be considered. First, there is considerable evidence that the condition can be prevented from occurring in the first place, which is obviously the preferable solution . In the contemporary management of surgical lesions of the lumbar spine, most commonly ruptured discs, there are several important measures which, if adhered to, will result in a greatly reduced incidence of the development of arachnoiditis . These measures will come to light as the study is pursued . However, once one is confronted with fully developed spinal adhesive arachnoiditis, it has been our experience that intradural operation offers the best hope of at least partial relief of a most distressing condition for the patient and of a complex clinical problem for the attending surgeon . Spinal adhesive arachnoiditis can be caused by a number of conditions . Tuberculosis, syphilis, meningitis, and spinal cord tumour are known causes .

Address reprint requests tar Dr. R .A. Dolan, 502-Medical Arts Building, Hamilton, Ontario, Canada, LSN IT8 . Received October 10, 1992 ; accepted November 19, 1992 . 0 1993 by Elsevier Science Publishing Co ., Inc .

However, compared to lumbar disc disease and its treatments, these other conditions are comparatively rare . It is apparent from a review of the literature and from clinical experience that the introduction of various contrast materials for myelographic study into the spinal canal has been an important cause of the condition in the past and a considerable number of patients continue to present with arachnoidal adhesions due to this foreign body introduction . In the early reports of arachnoiditis associated with lumbar disc disease, the contrast materials used, Pantopaque and Lipiodol, are oil-based and appear to be important offenders in the development of arachnoiditis . Lipiodol was perhaps the first oil-based contrast agent in general use . It was later largely replaced by Pantopaque which was a much more satisfactory material in all respects and much less irritative than Lipiodol. The water-based contrasts are less common etiologic agents . The closer the contrast material is to isomolarity the less likely the chance of adhesions developing . A material now in use, Iohexol Parenteral (phentermine hydrochloride), is a water-soluble isomolaric compound which is reabsorbed by the cerebrospinal fluid and no attempt to remove it is required . This infers that some of the studies to be reviewed are now mainly of historical interest . However, because of the very long history of the disorder in many cases, there presumably now exists an appreciable number of individuals who will be presenting from time to time with history and findings, both clinical and radiological, strongly suggestive of arachnoiditis caused by the nonabsorbable contrast materials . There seems little doubt that the presence of a ruptured disc and later operation for its removal are prime contributing factors in initiating arachnoiditis . If a degree of spinal stenosis is present and the removal of the disc material itself proves difficult, it is likely that repeated instrumentation of the dura and its contained pia and arachnid membranes can produce a reaction in these delicate membranes, leading to arachnoiditis . The lesions associated with arachnoiditis are usually discovered at myelography and/or operation . When the myelographic defects do not conform to the picture seen in a classical lumbar disc condition, then arachnoiditis is probably the presenting pathological condition . Before proceeding with the discussion regarding the treatment of established arachnoiditis, it is important 0090-3019/93/$6 .00



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first to look at measures to avoid the development of arachnoiditis . In several clinics known to the author, routine myelography carried out prior to dealing surgically with the offending disc is not considered desirable . When one is looking at a classical lumbar disc protrusion clinical picture with requisite supporting historical evidence and findings on physical examination, the chances are excellent that a pathological disc will be encountered . Thus, one has avoided two important conditions which contribute to the development of arachnoiditis . One is the invasion and disturbance of the spinal canal and its contents by the myelographic procedure itself and, more importantly, the intradural deposit of a potentially irritative foreign body, the contrast material being used . A second measure to reduce the chances for arachnoiditis, when myelography is considered necessary, is to use only the latest type of contrast material, namely a water-based material of known isomolarity such as lohexol Injectable . This material is quickly reabsorbed by the cerebrospinal fluid and needle aspiration is not required . Before proceeding further, consideration of noninvasive diagnostic techniques is in order . First is computerized axial tomography or CT scanning . This radiological procedure gives an excellent depiction of the intraspinal contents, is noninvasive and may be quite sufficient to make the diagnosis . Secondly is Nuclear Magnetic Resonance Imaging, which gives a striking view of the entire cerebrospinal canal if required . Having reviewed the measures to prevent the occurrence of the subject condition, we now must consider patients, often in agonizing pain, who may become very depressed and are usually dependent on analgesics . While it is our contention that gperation is often of considerable benefit, it is recognized that it is a controversial procedure and so other methods of pain relief are first attempted . A few of our patients have been subjected to cord stimulation techniques and the implantation of electrodes with some success . When this series was first begun, we tried unilateral cordotomy if the pain was predominantly on one side and several fairly successful results were obtained . However, in .recent years, this technique has been gradually phased out because of its radical and destructive nature . The operative technique consists of a conventional decompressive laminectomy approach, the unroofing of the dura mater, followed by opening of the dura mater and exposure of the cauda equina . In advanced cases particularly, a nonpulsatile mass of matted nerve roots is often encountered . There is usually a partial or total block of spinal fluid flow (Figure 1) . Then very carefully, an attempt is made to separate the nerve roots, one from the other, and to "tease out" the white collagenous material that is binding the nerve elements of the cauda

Dolan

equina together . Frequently, the nerve roots are adherent to the dura mater . Great care must be exercised to avoid stretching and tearing any of the roots (Figure 2) . A patient who wakens with saddle anaesthesia and bowel and bladder incontinence is rightfully very disappointed in what is a very unhappy situation for all concerned . There is no doubt that the adhesions can and do reform, but one is impressed that, in an appreciable number of cases, there is marked improvement, while several more patients are grateful for definite, though partial relief. A few can return to work ; others find themselves quite mobile, but are not able to sustain a full work day . Unfortunately, a definite percentage are not improved and become quite depressed and dependent on narcotic medication . In the group under consideration, one man has committed suicide, while two or three have threatened suicide . Frequently, repeat operations have been helpful . There are several complications of the operation which must be faced . First is spinal fluid leak and this hinges largely on whether the dura mater is left open or closed . When the nerve roots are adherent to the dura mater, it seems wiser to leave the dura open . We then cover the opening by sewing in a dural substitute such as Silastic, still leaving more room for the nerve roots . It should be pointed out that the use of Silastic is not without certain risks . There are reports of cases where the presence of Silastic resulted in subdural haemorrhage in the brain or spinal canal . Fortunately, we did not have this experience . Another complication is pseudomeningocele, which is a leaking of CSF under the skin and requires operative repair . The secret of a dry result in meticulous closure of all the muscular and skin layers . The fundamental question to be asked is whether operation for well-established arachnoiditis is the ultimate best management of the condition when all other measures have been exhausted . The operative approach remains controversial . However, it has been our experience that operation has the potential to provide effective relief for varying periods of time . When one considers the agonizing pain many patients endure, any treatment that offers a reasonable chance of improvement and can render the quality of life more bearable appears justified . Review of Literature and Discussion Hart 151 defines the condition as a localized encapsulation in the arachnoid compartment of the spinal canal producing symptoms and signs of compression of the spinal cord or cauda equina. Guyer et al 14] studied 50 patients with a long followup amounting to 21 years . Ninety percent originally had intervertebral disc disease, Pantopaque myelography,



Spinal Adhesive Arachnoiditis

and subsequent surgery prior to developing arachnoiditis . Once the diagnosis was made, the pain and functional disability tended to remain the same . This has been our experience also . The clinical presentation of our patients was essentially the same year after year . Quiles et al [6] reviewed 38 patients with arachnoiditis . Surgery and contrast material were the most important factors . However, they found that arachnoiditis could occur without previous surgery . Myelographic findings showed a complete block in 19 out of 30 patients . Pathological abnormalities included lack of

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Figure 1 . This photograph illustrates the lumbar nerve roots adherent to each other with deformation of the normal architecture of the cauda equina at obvious points prior to attempts at separation of the adhesions .

dural pulsation, meningeal thickening, absence of cerebrospinal fluid, nerve roots embedded in thick, fibrous tissue, fibrosis and hyalinization of the arachnoid . Chronic inflammatory cells were present in only three cases . The pathogenesis of arachnoiditis was thought by Quiles et al [6) to be similar to the adhesions noted in



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Figure 2 . This illartration shows the process of separation of the adhesions . Above and below remain some adhesions to be separated .

repair or injury to serous membranes elsewhere in the body. However, phagocytes and enzymes are washed away by the cerebrospinal fluid and so forming fibrous bands are not eradicated . Arachnoiditis is the end result of repair of the arachnoid inflammation and this end stage is devoid of the signs of inflammation . Skalpe [7] discusses arachnoiditis after myelography .

Dolan

Pantopaque was widely used . This oil-based medium has been involved in numerous occurrences of arachnoiditis . Some media, methiodal sodium, meglumine iothalamate, can cause convulsions . Metrizamide, which is isotonic with CSF, was thought much safer in moderate volumes . The lower the osmolarity, the less toxic the material . The present author believes that, with the use of Iohexol Parenteral, we have now reached a point where the contrast material is so nonirritative that it ceases to be a problem .



Spinal Adhesive Arachnoiditis

Smolik et at [81 presented patients who demonstrated arachnoiditis as a complication of the lumbar disc operation . Some patients were progressively incapacitated following surgery . Four of their patients developed a partial or complete spinal block (on myelography) following operation for a disc lesion . These patients were all treated by lysis or dissection of the adhesions binding the nerve roots together . These authors found that this procedure was of definite benefit. It is our opinion that, if dissection is not carried out, operation is useless . Auld et al [11 presented 25 patients who developed spinal radiculopathy after disc surgery . All had intractable pain and most required pain-relieving procedures such as cordotomy . However, in seven of their patients, a very similar postoperative syndrome occurred with spasm of the leg muscles and cramps, radicular pain, and chills lasting from three to 20 days . Many, but not all, became free of pain for a time . However, all seven later developed arachnoiditis . All had myelography within a week prior to the initial disc operation . In six of these patients, the dura was opened, revealing arachnoiditis . It was concluded that silent arachnoiditis can occur with symptoms developing later . Myelography was implicated in some cases of arachnoiditis following the use of oil or water-soluble contrast media . It was felt that corticosteroids might reduce the development of adhesions . Accordingly, if this syndrome is recognized, steroids may be useful as a preventative measure . Benner et al [21 reviewed 68 cases . A combination of oil myelography and spinal surgery led to arachnoiditis in almost all cases . Presentations were typical of multiple nerve root involvement producing sphincter disturbances, motor, sensory, and reflex changes in two-thirds of the cases . In a review of all procedures, Benner et al [21 reported an average of 3 .6 procedures per patient prior to myelographic diagnosis and a further 2 .2 procedures following diagnosis . Myelography and surgery comprised the procedures in 60 out of 68 cases . Forty-seven percent had new complaints or an exacerbation of previously developed complaints following the designated procedure leading to a myelogram showing arachnoiditis . Fifty-three percent had relatively symptom-free intervals following surgery for three months to nine years . The clinical syndrome, according to Benner et al [2), consisted of back pain and leg pain, motor, sensory and reflex changes indicating widespread deficits . The majority of symptoms were bilateral or attributable to multiple root involvement . Sphincter disturbance was noted in a small percentage of cases . CSF protein varied from 11 to 126 with an average of 48% mg. Cell counts varied from 0 to 70 . The mean was three cells per cc .

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Burton [31 reported on 100 patients with lumbosacral arachnoiditis seen at surgery or on myelography . The condition is common in patients with FBSS-Failed Back Surgery Syndrome . Pantopaque was an important factor. In these cases, all had low back pain and leg pain accentuated by activity and straight leg raising, tenderness at the sciatic notch, limited trunk movement and muscle spasm . The group of patients averaged 3 .6 back operations and 2 .6 Pantopaque myelograms per operation . The initial diagnosis was degenerative or herniated disc . Additional diagnostic studies and discotomies did not relieve increasing symptoms . Criteria for the Judgment of Results of Operation We have arbitrarily categorized our results as Excellent, Good, Fair and Poor . It must be emphasized that none of our patients were entirely pain-free . The stability, psychological makeup, and dependence on analgesic medication of each patient are matters of prime importance . Only the most stable individuals, in our opinion, could undergo months and perhaps years of unrelenting pain without developing a certain emotional reaction and without requiring varying amounts of analgesic medication . We shall now describe the general condition, ability to work and other characteristics in each of these criteria . Excellent : Two patients . Two males who have returned to fairly regular work, enabling them to support themselves and their families . They do not complain unduly and require comparatively light medication . Good: Thirteen patients . These patients are not working regularly, but make occasional attempts at work . These individuals are usually cheerful and optimistic . They have come to terms with their disability and pain . They all require regular medication, but have adjusted to an agreed-upon dosage and do not demand stronger analgesics . Fair. Nineteen patients . This group of patients is totally unable to work, but they are coping with their pain . Some have definite neurological defects, both sensory and motor. All require reasonably strong medication . On the whole, they are quite cheerful and do not exhibit suicidal ideation . Poor : Seven patients . These individuals are all depressed and some have expressed alarming thoughts suggesting suicide . One patient has committed suicide and two others are potentially suicidal . These patients present difficult management problems in that they constantly ask for increasing doses of strong analgesics . Some have gross neurological defects such as lower extremity weakness and bowel or bladder incontinence . This perplexing subject, arachnoiditis, has been dis-



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cussed with a number of colleagues . Opinions regarding the wisdom of the aggressive approach described above varied a great deal as might be expected . Doubtless, some thought that operation was not worthwhile, at least in some of the patients, and this was a legitimate viewpoint . However, our general conclusion was that operation, preceded by the use of absorbable, nonirritative contrast materials in the investigation, was helpful in that it resulted in a more bearable existence for the majority of patients dealt with . I thank my secretary, Mrs . Lois Luneberg, as well as Mrs . Karen Orescanin, Miss Margaret Barr, and the Health Records Services staff at Hamilton Civic Hospitals, General Division, for their invaluable assistance.

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References 1 . Auld AW . Chronic spinal arachnoiditis : A post-operative syndrome that may signal its onset . Spine 1978 ;3 :88-92 . 2 . Benner B, Ehni S . Spinal arachnoiditis . The postoperative variety in particular . Spine 1975 ;3 :40-1 . 3 . Burton CV. Lumbosacral arachnoiditis . Spine 1978 ;1 :24-30. 4 . Guyer DW, Wiltse LL, Eskay ML, Guyer BH . The long range prognosis of arachnoiditis . Spine 1989 ;14 :1332-41 . 5- Hart GM . Circumscribed serous spinal arachnoiditis simulating protruded lumbar disc, Case Report . Annals of Surgery 1958; 148 :266-70 . 6 . Quiles M, Marchisello PJ, Tsaris P . Lumbar adhesive arachnoiditis . Spine 1978;3 :45-50 . 7 . Skalpe 10 . Adhesive arachnoiditis following lumbar myelography. Spine 1978;3 :61-48 . Smolik EA, Nash FP . Lumbar spinal arachnoiditis . A complication of the intervertebral disc operation . Annals of Surgery 1951 ;133 :490-5 .