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`NUVASIVE 1036
`NuVasive, Inc. v. Warsaw Orthopedic, Inc.
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`
`
`H€UROSURG€RV
`
`OFFlCIflL JOURNAL OF THE: COHGR€§§ OF N€UROLOGICHL SURG€OH§
`
`contents
`
`Volume Iii/Number 5
`November 1983
`
`NEUROSURGERY (ISSN 0148-
`396X)
`is published monthly by
`The Congress of Neurological Sur-
`geons, 428 E. Preston Street. Bali
`timore. MD 21202 Annual dues
`include 360 for journal Subscrip-
`tion. Second class postage paid at
`Baltimore, MD. and at additional
`mailing offices. Postmaster: send
`address changes (Form 3579) to
`Williams (Er Wilkins, 428 l; Pres-
`ton St, Baltimore, MD ZIZOZ
`Subscription rates: $85 ($100 for»
`eign); institutions $l00 ($115 for.
`eign); single copy $12 (SM (or-
`eign), Copyright
`LE.)
`I983 by the
`Congress of Neurological Sur-
`geonsi
`
`Clinical and laboratory reports
`479
`
`Ancurysmal Rebleeding: A Preliminary
`Report from the Cooperative Aneu-
`rysm Study
`Neal F. Kassell, M.D., and James C.
`Torner, MS
`Hydraulic Model of Myogenic Auto—
`regulation and the Cerebrovascular
`Bed: The EtTects of Altering Systemic
`Arterial Pressure
`Harold D. Pormoy, M.D., Michael
`Chopp, PhD. and Craig Branch, A/IS.
`Role of Radiation Therapy in the
`Treatment of Cerebral Oligodendro-
`glioma: An Analysis of 57 Cases and a
`Literature Review
`D. Peter Reedy, M.D., Janet W. Bay.
`AID, and Joseph F. Hahn, MD.
`Posterior—Lateral Foraminotomy as an
`Exclusive Operative Technique for Cer-
`vical Radiculopathy: A Review of 846
`Consecutively Operated Cases
`Charles M. Henderson, MD, Robert
`G Ilennesxs'vit, MD” Henry M. Sltltet‘.
`Jr, MD, and E. Grant Shaekellitrd.
`BS.
`
`499
`
`504
`
`523
`
`Hormone Binding in Brain Tumors
`Roberta P. Click, M.D., Agostitto Mol-
`teni, MD.. Ph.D., and Ellen M. Fats,
`MS.
`Angiographic Demonstration of Post—
`operative Cortical Artery Stenosis ln-
`duced by Biemcr Temporary Clips
`Jack M. Ft’ll/I, Ml)” Manuel Dttjoi’n)‘,
`M.D., and NirKoysmts/(y, MD.
`Sequential Morphological Changes in
`the Dog Brain after Interstitial Iodine—
`l25 Irradiation
`()stertag. M.D., Klaus
`Christoph 8.
`”angel. M.D.. Peter Warn/(e, M.D..
`Gunthild Lombeek, M.I)., and Paul
`Kleihues, MD.
`Neuropsychological Sequclac of Minor
`Head Injury
`Jelfi'ey T. Barth, Ph.D.. Stephen N.
`Maetrt'ocela', Ph.D.. Bruno Giordanl.
`Ph.D., Rebeca: Rimel. RN. John A.
`Jane, M.D., and Thomas J. Boll. Phi).
`
`
`529
`
`548
`
`VJ! t). '.n
`
`Three—Dimensional Reconstruction of
`Craniofacial Deformity Using Com—
`puted Tomography
`D, C. Hemmy, Ml), D, J. David,
`M.B.B.S., and Gabor T. Herman,
`PhD.
`Percutaneous Discectomy: An Alter-
`native to Chemonucleolysis?
`William A. Friedman, MD.
`Congenital Hydrocephalus Revealed in
`the Inbred Rat, LEW/Jms
`Salosht' Sasakt', D.V.M., Htloxhi Goto,
`D.lt’.M., Hide/(1‘ Nagano, Koji Furuya,
`Di Dill/1., Yoshitaka ()mala, D. V.M.,
`Kyotaro Kanazawa, M.D., Ktyos/n' Su-
`zuki, fi/[.D., Katya/<0 51.1610, and Hart-
`mnt Col/mann, MD.
`Degenerative S pondylolisthesis with an
`Intact Neural Arch: A Review of 60
`Cases with an Analysis ofClinical Find—
`ings and the Development of Surgical
`Management
`Nancy E. Epstetn, M.D., Joseph A. Ep-
`stein, M.D., Robert Carras, MI). and
`Leroy S. Levine. MD.
`Use of an Anal Sphincter Pressure
`Monitor during Operations on the Sac-
`ral Spinal Cord and Nerve Roots
`Dachltng Pang, M.D., and Kenneth
`Casey, M.1).
`Brief communications
`569
`
`572
`
`Do We Need to Cross Match Blood for
`Elective Laminectomy‘?
`Delta P. Sarmu, MD.
`Primary Malignant Nerve Sheath Tu—
`mor of the Gasserian Ganglion: A Re—
`port of Two Cases
`W. J. Levy, M.D., L. .xlnsbat'lier, M.D.,.
`.1. Ever. M. D., A. Nztlklewiez, M.D..
`and J. Frat/tin, Ml)
`Spinal Cord Arteriovenous Malforma-
`tions Associated with Spinal Aneu-
`rysms
`Sustmm i'lilt'yarnoto, M.D., Hariihileo
`Ktkta'ln', M.[)., Jan Kurosawa, M.D..
`Toxhlo Ikota, M.D., and lzumt Nagata,
`MDi
`
`Contents continues next page
`
` 2
`
`

`

`0 148-396X/83/1305-0542$02.00/0
`NEUROSURGERY
`Copyright O 1983 by the Congress of Neurolog~cal Surgeons
`
`Vol. 13. No. 5. 1983
`Printed in U.S.A.
`
`Percutaneous Discectomy: An Alternative to
`Chemonucleolysis?
`
`William A. Friedman, M.D.
`Depur!menr of Ne:elrrologlcol Slrrgery, Uni\>ersil.v of Floridu. Gainesville, Florida
`
`At the University of Florida, a new technique for lumbar disc removal, called percutaneous discectomy, has been
`explored. This procedure may be performed under general or local anesthesia, frequently takes less than 15 minutes,
`and is generally bloodless. The patient selection process and the surgical technique are presented in detail. A total of
`nine patients have undergone percutaneous discectomy. Seven had clear radiculopathies with appropriate radiographic
`findings, and they all have had excellent relief of symptoms. Two patients presented with intractable low back pain,
`bilateral mechanical findings, and central disc herniations on sadlographic examination. One experienced good relief
`and one did not. Three patients had several days of paraspinous spasm after the procedure, and one complained of a
`lower extremity dysesthetic sensation that persisted for several weeks after operation. Our early experience with
`percutaneous discectomy suggests that it is a technically easy procedure that may prove, in carefully selected cases, to
`be a viable alternative to other discectomy techniques. (ATeurosurgery 13:542-547, 1983)
`Key words: Back pain, Chemonucleolysis, Disc herniation. Intervertebral disc displacement, Lumbar disc surgery,
`Percutaneous discectomy, Radiculopathy
`
`INTRODUCTION
`
`Recent months have witnessed a resurgence of interest in
`less invasive methods of treating lumbar disc disease, most
`notably chemonucleolysis. At the University of Florida, an
`alternative technique, called percutaneous discectomy, has
`been utilized on a small group of patients. The methods of
`patient selection, details of operative technique, and early
`clinical results are reported.
`
`METHODS
`
`All patients considered for this procedure presented with
`complaints of low back or extremity pain, refractory to con-
`servative therapy. Additionally, all had neurological or me-
`chanical signs consistent with lumbar disc disease. As it was
`thought unlikely that this technique would be of benefit to
`patients with disc fragments no longer in continuity with the
`disc space, efforts were made to exclude this possibility radi-
`ographically (2, 7). All patients underwent lumbar computed
`tomographic (CT) scanning and metrizarnide lumbar myelog-
`raphy. If these studies suggested vertical migration of the
`herniated disc, either under or through the posterior longitu-
`dinal ligament, the patient underwent a routine laminotomy
`and discectomy. No patient with a prior history of lumbar
`disc operation was considered for this study.
`A further goal of the screening process was the identification
`of aberrant retroperitoneal structures that might lie in the
`projected surgical path. Of primary interest were the courses
`of the abdominal great vessels (aorta, vena cava, and iliac
`vessels) and the large bowel (8). Patients were given Gastro-
`grafin (diatrizoate meglumine and diatrizoate sodium; E. R.
`Squibb & Sons, Princeton, New Jersey) and, 4 hours later,
`were placed in their projected surgical position within a body
`scanner. A single transaxial scan, performed at the level of
`the upper iliac crest, readily delineated the course of these
`structures (Fig. I). One patient was denied percutaneous
`discectomy because his abdominal CT scan revealed that his
`
`ascending colon lay directly in the surgical path (Fig. 2). Of
`course, no patient with a prior history of retroperitoneal
`operation was considered for this procedure.
`
`Operative technique
`This procedure can be performed under either general or
`local anesthesia. ~ l t h o ~ g h our initial experience has involved
`
`FIG. I . A CT scan was performed just abovc the level of the iliac
`crest 4 hours after the oral administration of Gastrograhn. The
`projected retroperitoneal surgical path is well visualized and unob-
`structed (arro~t,s). The ascending colon, filled with contrast agent, is
`seen well anterior. The aorta and vena cava are identified in their
`usual locations, rrnmediately anterior to the vertebral body.
`
` 3
`
`

`

`November 1983
`
`FIG. 2. This CT scan, performed In an identical fashion but In a
`very muscular patient, shows the ascending colon (arr'okt~) clearly in
`the projected surgical path. A large psoas muscle lies between the
`colon and the lateral aspect of the vertebral body.
`
`PERCUTANEOUS DISCECTOMY
`
`543
`
`general anesthesia, others report very satisfactory results using
`local anesthetic supplemented with intravenous Innovar (Cri-
`tikon, McNeilab, Inc., Irvine, California) (Jacobson RE: Per-
`sonal communication, 1983). After the induction of satisfac-
`tory anesthesia, the patient is placed in the lateral decubitus
`position, with the painful leg down. A roll is placed under the
`dependent flank to rotate the superior iliac crest out of the
`projected surgical path. A C-arm fluoroscope with image
`intensification is positioned for lateral lumbar spine radiog-
`raphy. The appropriate interspace is identified with fluoros-
`copy, and a I-in. skin incision is marked at that level, just
`over the iliac crest. The field is then prepared and draped.
`After the skin is incised, a specially designed speculum is
`inserted, under x-ray control, through the psoas muscle to the
`midpoint of the lateral surface of the desired interspace (Fig.
`3). The speculum is opened and a 40 French chest tube, with
`trocar in place, is inserted. The speculum and trocar are then
`removed, leaving the chest tube in position. An 18 gauge K-
`wire is then passed through the chest tube and popped through
`the anulus of the disc space. This wire, which prevents migra-
`tion of the chest tube, is then bent downward and cut, so that
`it is out ofthe way. Utilizing specially lengthened instruments,
`the surgeon incises the anulus of the disc with a # I 5 blade,
`and the disc is removed piecemeal with pituitary rongeurs
`(Figs. 4 and 5). With the pathological side inferior, a down-
`bit~ng rongeur reaches very easily into the posterolateral aspect
`
`FIG. 3. Artist's rendition shows a special speculum positioned at
`the lateral aspect of the pathological interspace. Note that the side of
`the herniation is down. A 40 French chest tube, with trocar in place,
`is inserted.
`
`FIG. 4. After the trocar and speculum are removed, the disc anulus
`is incised. The previously i n s e ~ ~ e d K-wire is not shown (for greater
`clarity).
`
` 4
`
`

`

`544
`
`FRIEDMAN
`.,Tm. v w ~
`~
`
`1:-
`
`+
`
`'
`
`i
`
`-.
`- w ~
`
`*
`
`Neurosurgery, Vol. 13, No. s
`
`r
`
`Case 2
`This 58-year-old man presented with a 15-year history of
`low back pain. In addition, he had previously suffered a
`traumatic amputation of his right leg and a subsequent reflex
`sympathetic dystrophy, which was totally relieved by a right
`lumbar sympathectomy. He complained of a 3-week history
`of severe left sciatica, unrelieved by conservative therapy.
`Physical examination disclosed a markedly positive left Las-
`kgue's maneuver. The neurological examination was signifi-
`left tibialis anterior, a -2 left EHL, an absent
`cant for a -1
`ankle reflex, and hypalgesia of the left foot (stocking pattern).
`A CT scan and m yelogram suggested the presence of a large
`L-4, L-5 disc fragment no longer in continuity with the disc
`space (Fig. 8). Furthermore, his previous retroperitoneal op-
`eration had rendered him a high risk for the percutaneous
`procedure. Consequently, he underwent a left L-4, L-5 lami-
`notomy, with the removal of a large free fragment disc that
`had migrated inferior to the interspace. At the time of dis-
`charge, his pain and mechanical findings had resolved, al-
`though his neurological examination was unchanged.
`
`RESULTS
`
`At the time of this writing, a total of nine patients have
`undergone percutaneous discectomy at the University of Flor-
`ida. The pertinent patient data are listed in Table 1. Of the
`seven patients who presented with complaints of sciatica, all
`
`FIG. 5. The nucleus pulposus is removed in a piecemeal fashion.
`
`of the disc space, completing the discectomy (Fig. 6). Ruo-
`roscopic control is used to prevent the rongeur from biting
`too far anterior (great vessels) or posterior (epidural space).
`The wound is then thoroughly irrigated, the chest tube is
`withdrawn, and the subcutaneous tissue and skin are closed.
`The operative time ranges from 15 to 30 minutes.
`
`ILLUSTRATIVE CASE REPORTS
`
`The following brief case reports are presented to further
`jllustrate the principles of patient selection and surgery.
`
`Case /
`This 52-year-old man presented wlth a 2-year history of
`low back pain and a 2-month history of left sciatica, refractory
`to conservative therapy. Physical examination disclosed a
`positive left Laskgue's maneuver at 45" and a positive crossed
`straight leg raising test. The neurological examination was
`significant for a -2 left extensor hallucis longus (EHL), absent
`ankle jerks bilaterally, and hypalgesia over the dorsal and
`lateral left foot. A CT scan and a metrizamide myelogram
`were consistent with a left-sided herniated L-4, L-5 disc in
`continuity with the disc space (Fig. 7). On November 3, 1982,
`he underwent a percutaneous discectomy (L-4, L-5). Three
`days later he was discharged with no pain, negative mechan-
`ical findings, and an unchanged neurological examination.
`Follow-up at 6 months disclosed that he was working full-
`time and had no low back or leg pain.
`
`FIG. 6. A modified "down-biting" pituitary rongeur is utilized
`remove the omending posterolateral portion of the disc.
`
` 5
`
`

`

`November 1983
`
`PERCUTANEOUS DISCECTOMY
`
`545
`
`FIG. 7. Case 1. A, anteroposterior view of a rnetrizamide lumbar myelogram demonstrates ampi~tation of the left L-5 nerve root. B. lateral
`view of the rnetrizamide lumbar myelogram demonstrates a focal bulge, apparentlp In con ti nu it!^ with the L-4. L-5 interspace. C, CT scan
`through the L-4. L-5 interspace demonstrates obliteration ol' the epidural fat that normally delineates the thecal sac and nerve root sleeves. This
`is consistent with a disc herniated centrally and to the left, in continuity with the interspace.
`
`had significant relief after operation. The other two patients
`presented with complaints of intractable low back pain, with
`bilateral mechanical findings and normal neurological ex-
`aminations. As their radiography was consistent with central
`disc herniations and they were unresponsive to prolonged
`conservative therapy, they were offered surgical therapy. One
`was helped and one was not. Three patients experienced
`paraspinous muscle spasm for up to I week after operation.
`One patient complained of a dysesthetic leg sensation on the
`side of surgical instrumentation, which resolved after several
`weeks. There have been no other complications. The long
`term results will only be ascertained after further follow-up.
`
`DISCUSSION
`
`The potential advantages of percutaneous discectomy are
`very similar to those of chemonucleolysis. As there is no
`lumbar incision, muscle stripping, or bone removal, the de-
`gree of postoperative wound pain is minimal. This leads to a
`greatly shortened hospital stay. Further, the epidural space is
`never violated and the nerve root is never directly manipu-
`lated. Consequently, there is no opportunity for hemorrhage
`and scarring. These factors may reduce the incidence of
`increased neurological deficit after operation and late failure
`secondary to arachnoiditis.
`
` 6
`
`

`

`546
`
`FRIEDMAN
`
`Neurosurgery, Vol. 13, No. 5
`
`FIG. 8. Case 2. A , anteroposterior view o f a metrizamide lumbar myelogram demonstrates focal amputation of the left L-5 nerve root. 0, CT
`scan performed immediately after myelography demonstrates a large. left-sided, epidural mass indenting the thecal sack. The mass etrect was
`greatest over the L-5 vertebral body. suggesting the presence of a large herniated d ~ s c fragment that had migrated inferior to the disc space.
`
`Age (yr)
`43
`6 3
`32
`4 3
`52
`44
`
`Symptom
`R sciatica
`L sciatica
`L sciatica
`R sciatica
`L sciatica
`Low back pain
`
`L sciatica
`L sciatica
`Low back pain
`"Abbreviations: R, right: L, left.
`
`T A B L E I
`Dara on Pntienls Treafed b,~. Percccluneoi~s Disceclomyo
`--
`Discecto~ny Level
`Result
`Complication
`Relief
`Paraspinous spasm
`-
`Relief
`Relief
`Rel~ef
`Relief
`Rel~ef
`
`-
`Paraspinous spasm, lower extremity
`dysesthesia
`-
`-
`Paraspinous spasm
`
`Relief
`Relief
`No relief
`
`Follow-up (mo)
`6
`6
`6
`6
`6
`3
`
`There are also potential disadvantages of this technique.
`Structures coursing through this area of the retroperitoneurn
`include the aorta, vena cava, iliac and lumbar vessels, large
`bowel, ureters, sympathetic chain, lymphatic chain, and lurn-
`bar plexus (8). Positioning the patient on his side results in
`rotation of the peritoneal contents, ureter, and large bowel
`a\vay from the surgical path. This should be verified by
`abdominal CT scan, as retroperitoneal scarring or a very
`muscular body habitus may preclude this approach. Addition-
`ally, the CT scan can be utilized to verify that the course of
`the major vessels, which may be tortuous in the elderly, is
`
`well away from the surgical path. Any injury to the lymphatics
`or small vessels seems to be readily tamponaded by the psoas
`muscle. A lesion of the sympathetic chain at one level would
`be unlikely to cause even a minimal sympathectomy of the
`ipsilateral leg. Available anatomical studies reveal that several
`lumbar plexus branches are near the projected surgical path
`at L-4. L-5 ( I , 5 , 8). A t L-5, S-1, the femoral nerve sweeps
`forward, over the lateral surface of the psoas, in even closer
`proximity to the surgical path. The iliac vessels, which form
`at or below L-4, L-5, are also sweeping laterally and closer. In
`addition, the height of the iliac crest often renders impossible
`
` 7
`
`

`

`entry to the L-5, S- 1 interspace from the side without drilling
`through the crest. For these reasons, we have not used this
`technique at L-5, S-I. Finally, the blunt speculum used is
`likely to sweep aside any aberrant structures that may lie in
`the surgical path. Thc one instance of temporary leg dyses-
`thesis that we observed probably resulted from contusion of
`a lumbar plexus branch as the speculum was inserted. Expe-
`rience elsewhere confirms our impression that the incidence
`of complications related to instrumentation is extremely low
`(Jacobson RE: Personal communication, 1983).
`Chemonucleolysis is commonly performed under general
`anesthesia. Needle insertion, which can be difficult, especially
`at L-5, S-1, is often followed hy discography and a test
`injection of enzyme before actual chemonucleolysis (4). The
`reported incidence of anaphylaxis in women is 2.5% ( 1 %
`overall) (4, 6). Other complications include a high incidence
`of postoperative back pain (50%) and paraspinous muscle
`spasm (25%). Minor sensitivity reactions, paralytic ileus, and
`urinary retention are seen with lesser frequency (3.4). Because
`the path of needle insertion is extremely close to exiting
`lumbar nerve roots, it is likely that they are occasionally
`impaled during this procedure. Nonetheless. the overall results
`from chemonucleolysis seem satisfactory and have gained
`wide acceptance. The operative time for percutaneous discec-
`tomy is considerably shorter than that reported for chemo-
`nucleolysis and, of course. the risk of anaphylaxis associated
`with chymopapain injection is eliminated. Our early experi-
`ence with percutaneous discectomy suggests that it is a tech-
`nically easy procedure that may prove, in carefully selected
`cases. to be a viable alternative to other discectomy tech-
`niques.
`
`ACKNOWLEDGMENT
`
`The author thanks Dr. Robert Jacobson for teaching him
`the percutaneous discectomy technique. Dr. Jacobson devel-
`oped this methodology.
`
`Received for publ~cat~on, April 2 I , 1983; accepted. July 8. 1983.
`Reprint requests: William .A. Friedrnan. M.D.. Neurological Sur-
`ge~-y. Box 5-265, JHM Health Center, University of Florida, Gaines-
`ville. Florida 326 10.
`
`PERCUTANEOUS DISCECTOMY
`
`547
`
`REFERENCES
`
`I . Grant JCB: An A~las of Analomv. Baltimore, Williams and
`Wilkins, 1972, p 190.
`2. Haughton VM. Eldevick OP, Magnaes B, Amundsen P: A pro-
`spective comparison of computed tomography and myelography
`in the diagnosis of herniated lumbar discs. Radiology I42:103-
`1 10, 1982.
`3. McCulloch 5.4: Chemonucleolysis: Experience with 2000 cases.
`Clin Orthop 146: 128- 135, 1980.
`4. Nordby EJ: Syllabus-Postgraduate Course on lntradiscal Ther-
`apy (sponsored by the American Association of Neurological
`Surgeons and the Anlcrican Academy of Orthopaedic Surgeons).
`Chicago, 1982.
`5. Pernkopf E: ,4111s of Tc~pogr~yhical and Applied Ilumun Anat-
`omj.. Baltimore, Urban and Schwarzenberg, 1980, pp 184-1 87.
`6. Watts C. Williams OB, Goldstein G: Sensitivity reactions to
`intradiscal injeclion of chymopapain during general anesthesia.
`Anesthesiology 44:437-439. 1976.
`7. Williams AL, Haughton VM, Daniels DL, Thorntnn RS: CT
`recognition of lateral lumbar disk herniation. 4JR 139:345-347,
`1982.
`Hllr?zun Anarom~~. New York,
`8. Woodburne RT: E.r.\cntial.c
`Oxford University Press. 1973, pp 449-464.
`
`COMMENT
`
`-
`
`Dr. Friedman describes an ingenious alternative to intra-
`discal therapy for the herniated disc that is not sequestered.
`The number of patients is srnall and the time elapsed is not
`long enough to judge success or recurrence. The short term
`results seem coniparable to those of conventional operation
`or intradiscal therapy. Only a longer patient evaluation will
`determine whether this is a viable technique that may be
`useful in the management of these problems. The potential
`pitfalls arc many and the procedures certainly cannot he
`recommended for general use a t present. It is an interesting
`technique that has real rnerit and should be explored by a
`small number of individuals dedicated to the management of
`the herniated disc and innovative techniques of surgery. Until
`we have comparable evaluations to compare the results of
`this procedure with currently accepted techniques. it will not
`be possihle to place it appropriately in the surgical armamen-
`tarium.
`
`Don M. Long, h1.D.
`Balrimorr, Mrtrylurid
`
` 8
`
`