spinal pelvic fixation in patients with lumbosacral neoplasms · quired spinal–pelvic fixation...

URGICAL resection followed by internal fixation toachieve stabilization is often indicated in the man-agement of patients with primary or metastatic lum-

bosacral neoplasms. Primary sacral tumors are amenableto complete en bloc resection for possible cure. Palliationis the goal in cases of metastatic lumbosacral tumors. Pal-liative goals include restoration of neurological functionor prevention of further neurological decline, as well asthe alleviation of pain. The destructive process of the tu-mors and the removal of such tumors often necessitate astabilization procedure.

Primary and metastatic neoplasms of the LSJ frequentlypose a complex problem for surgical management and sta-

bilization because of anatomical and biomechanical factorsof this transition zone between spine and pelvis. The LSJhas been considered by some to be the most difficult por-tion of the spine at which to obtain a solid fusion,20 in partbecause of the large load carried and because of the angu-lar position of the sacrum, which produces unique load-bearing characteristics. This region also represents a transi-tion from the mobile spine to a relatively fixed pelvis thatplaces additional stress at the LSJ. These inherent biome-chanical factors of the LSJ combined with the destructiveelement of neoplastic processes and the treatment of suchdisease present a challenging problem in terms of spinalstabilization.

Various methods of sacral fixation exist. Use of a singlepair of sacral pedicle screws is often adequate to achievefixation in short segment cases in which minimal instabil-ity is demonstrated. More substantial fixation techniques

J. Neurosurg: Spine / Volume 92 / January, 2000

J Neurosurg (Spine 1) 92:61–70, 2000

Spinal–pelvic fixation in patients with lumbosacralneoplasms

ROBERT J. JACKSON, M.D., AND ZIYA L. GOKASLAN, M.D.

Department of Neurosurgery, Baylor College of Medicine, Houston, Texas; and Department ofNeurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas

Object. Primary and metastatic neoplasms of the lumbosacral junction frequently pose a complex problem for thesurgical management and stabilization of the spine because of the anatomical and biomechanical factors of this transi-tion zone between spine and pelvis. The authors have used a modification of the Galveston technique, originallydescribed by Allen and Ferguson in the treatment of scoliosis, to achieve rigid spinal–pelvic fixation in patients withlumbosacral neoplasms. The authors retrospectively reviewed their experience, with particular attention to method,pain relief, and neurological status.

Methods. From July 1994 through December 1998, 13 patients at the authors’ institution have required spinal–pelvicfixation secondary to instability caused by primary (eight cases) or metastatic (five cases) neoplasms. Previous treat-ment included spinal surgery in 10 (77%), radiation therapy in seven (54%), and/or chemotherapy in six (46%).Following tumor resection, fixation was achieved by intraoperative placement of contoured titanium rods bilaterallyinto the ilium. These rods were attached to the lumbar spine with pedicle screws and subsequently crosslinked.Arthrodesis was performed.

In the follow-up period of 3 to 50 months (average 20 months), nine (69%) of 13 patients were still alive. Therewere no cases of surgery-related death. Seven weeks postoperatively instrumentation failure occurred in one patientand was corrected by performing double L-rod spinal–pelvic fixation. Two patients experienced neurological dys-function (ankle weakness and neurogenic bladder) that was thought to be related to tumor resection rather than the fix-ation procedure. Neurological status improved in four patients and remained unchanged in seven patients. Ambulatorystatus improved in 62% (eight patients), remained unchanged in 23% (three patients), and worsened in 15% (twopatients). Spinal pain, as measured by a visual analog pain scale and determined by medication consumption was sig-nificantly reduced in 85% (11 cases).

Conclusions. In selected patients with primary or metastatic lumbosacral tumors, resection followed by modifiedGalveston L-rod spinal–pelvic fixation is an effective means of achieving stabilization that can provide significant painrelief and preserve ambulatory capacity.

KEY WORDS • spinal fixation • spine • metastasis • lumbosacral • tumor

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Abbreviations used in this paper: LOS = length of hospital stay;LSJ = lumbosacral junction; TLSO = thoracolumbosacral orthosis;VAS = visual analog scale.

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are required in cases in which a longer spinal fixationlength is required, such as in scoliosis and multilevel lum-bosacral fixation, or in cases in which gross instability isdemonstrated, such as that which occurs after large tumorresection or sacrectomy. Sacral pedicle screw pullout is acommon complication in these cases of longer segmentlength.10,24,25 In addition, because the body and/or pediclesof the sacrum are frequently compromised by tumor, theymay be resected in patients with neoplasms in this region,making the use of sacral pedicle screws unfeasible. Forthese reasons it is often necessary to perform lumbar toilium fixation, thereby bypassing the sacrum.

Allen and Ferguson2–5 originally described performing a lumbar–ilium L-rod pelvic fixation to treat scoliosis,pelvic obliquity, and degenerative processes of the LSJ,which became known as the Galveston technique of pel-vic fixation. We have modified this fixation technique byusing lumbar pedicle screw fixation in place of sublami-nar wire in patients with spinal–pelvic instability sec-ondary to lumbosacral tumors. With particular attention tomethod, pain relief, and neurological status, we have ret-rospectively reviewed our experience with spinal–pelvicfixation in patients harboring lumbosacral tumors.

Clinical Material and Methods

Patient Population

From July 1, 1994 to December 31, 1998, 802 spinal op-erations were performed in 621 patients by the surgeons ofthe neurosurgery service at The University of Texas M. D.Anderson Cancer Center. Thirteen of these patients re-quired spinal–pelvic fixation for instability due to primary(eight cases) or metastatic (five cases) neoplasms. Previoustreatment included spinal surgery in 77% (10) radiationtherapy in 54% (seven), and/or chemotherapy in 46% (six)of patients.

Indications for surgery varied depending on the type ofneoplasm. Primary sacral tumors are amenable to com-plete en bloc resection for possible cure. Palliation is thegoal in cases of metastatic lumbosacral tumors. Palliativeindications include restoration of neurological function orprevention of further neurological decline, as well as thealleviation of pain. All patients had an estimated life ex-pectancy that exceeded 3 months.

The patients’ records were retrospectively reviewed, anddata were collected on age, sex, and presence of primaryand metastatic disease. Medical treatment (chemotherapy,radiotherapy, or both) and history of previous spinal surgerywere reviewed (Table 1). Preoperative evaluation includedneurological examination, assessment of pain level, radiog-raphy, magnetic resonance imaging, and computerized to-mography scanning in selected cases. Neurological functionwas assessed, and each patient’s neurological status wasscored by the method of Frankel.14 A VAS27 was adminis-tered to measure pain status. The effectiveness of medica-tion and quantity of pain medication consumption were re-corded for all patients. Operative recorded data includedprocedure, number of levels internally fixed, duration ofsurgery, estimated blood loss, transfusions, and type of clo-sure. The postoperative LOS, number of days until ambula-tory, and complications were reviewed. Serial postoperativeneurological evaluation, VAS scores, and pain medication

consumption were recorded. The average length of followup was 20 months (range 3–50 months). Telephone inter-views were conducted with patients to obtain additional in-formation.

Operative Technique

Following endotracheal intubation and induction ofanesthesia, patients were positioned prone on gel bolsterswith great care to pad all pressure points adequately.Somatosensory evoked potential monitoring was used in-traoperatively to assess the physiological integrity of thespinal cord in selected cases. The dorsolumbar spine andsacrum were exposed via a midline incision in most cases.A lumbosacral flap was lifted from the sacrum and retract-ed laterally and rostrally (Fig. 1). This flap permits widelateral and caudal exposure without causing ischemic dam-age and retractor-related muscular injury that may occurwith straight lateral retraction of the dorsolumbosacralmusculature. Certain primary tumor resections required el-liptical incisions to remove adequately soft tissue and skininfiltrated with tumor. If radical resection was the goal,total sacrectomy was performed in cases of large, primarytumors of the sacrum that extended rostral to the S1–2level. In these cases an anterior approach was performedprior to posterior resection and stabilization.15 During theanterior portion of the procedure visceral and vascularstructures of the pelvis were mobilized from the tumor, andan L5–S1 anterior discectomy and partial ventral sacroiliacosteotomies were performed. A posterior approach resec-tion and stabilization procedure was performed severaldays later in patients who underwent total sacrectomy. En

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TABLE 1Demographic and clinical data obtained in 13 patients

undergoing spinal–pelvic fixation

age (yrs)range 26–74mean 45

sexmale 8female 5

tumor typeprimary tumors

chordoma 3giant cell 2chondrosarcoma 1unclassified spindle cell sarcoma 1myxopapillary ependymoma 1

metastaticrenal 2testicular 1breast 1colon 1

presenting symptomneurological compromise 13severe pain 8moderate pain 5

previous treatmentsurgery 10radiotherapy 7chemotherapy 6

follow-up period (mos)range 3–50mean 20


bloc resection was performed for primary tumors of thesacrum (Fig. 2). Metastatic tumors were generally removedin a piecemeal fashion by using routine neurosurgical tech-niques. In situations in which the tumor was too solid forsuction and too soft for high-speed drilling, we used anultrasonic aspirator (Cavitron Ultrasonic Aspirator; Valley-Lab, Inc., Boulder, CO). After the tumor was resected andthe neural elements were completely decompressed, atten-tion was turned to segmental fixation. In those patients inwhom total sacrectomy was performed, the procedure wasundertaken in two stages: anterior mobilization followedby a posterior resection and fixation at a later date.

The stabilization procedure used is a modification of Gal-veston technique of pelvic fixation.2–4 Instead of using lum-bar sublaminar wiring, we use pedicle screw fixation seg-mentally to attach the rods to the lumbar spine. This isthought to provide more security than the wiring technique,allowing a shorter fixation length and increased rigidi-ty.1,11,13,17,19,28 Additionally, in many of our patients laminec-tomy was required for tumor removal, which precludes theuse of sublaminar wiring. Rigid crosslinks were placedbetween the rods to provide increased torsional stability.Transiliac threaded rods were used to reconstruct the pelvicring in cases in which total sacrectomy was performed, asdescibed previously.15

Initially, screws (Universal Spinal System; Synthes Spine,

Paoli, PA) are placed bilaterally in the lumbar pedicles in astandard fashion.11,21,26,30 Intraoperative radiography is used toconfirm correct positioning. Using a high-speed burr drill, a6-mm hole is made in the cortex of the medial posterior iliaccrest at approximately the S2–3 level. This allows one to tapa 6-mm titanium pilot rod into the cancellous portion of theilium to create a path for the contoured rod (Fig. 3 left). Thistemporary rod is directed 1.5 cm above the sciatic notch andbetween the two cortices of the ilium, and it is tapped intoplace with a mallet to a depth of 6 to 9 cm. This pilot rod isthen removed, and a malleable template rod (wire) is insert-ed, subsequently contoured, and removed. A 6-mm titaniumrod is contoured to match the template rod (wire) by usingtube benders and a table vice (Fig. 3 center) and is subse-quently tapped into the ilium. The rod is attached to the lum-bar pedicle screws. Crosslinks are then placed between therods (Fig. 3 right). In cases requiring total sacrectomy, athreaded rod is placed through lateral to medial ilium, throughtibia or femoral allograft, and then through the opposite medi-al to lateral ilium to reconstruct the pelvic ring. Locking col-lars are placed on the transiliac rod to prevent lateral migra-tion of the rod. A combination of autograft, allograft, anddemineralized bone matrix is placed over selectively decorti-cated bone to promote arthrodesis. Closed suction drainagecatheters are placed as needed. Rotational or free myocuta-neous flap closure was necessary in five patients (38%) dueto the presence of a large soft-tissue defect caused duringtumor resection.

Postoperative Care

Most patients were observed in the surgical intensivecare unit overnight and were transferred to the neurosurgi-cal ward the next day. Those patients in whom surgery tookless time and in whom there was minimal blood loss wereobserved in the recovery room and were then transferred tothe neurosurgical ward. An external TLSO was used in fourcases (Cases 1–3 and 5; Table 2). Our first two patients toundergo total sacrectomy (Cases 1 and 2) were placed inexternal orthosis; in patients treated later in the series whounderwent total sacrectomy an external orthosis was notused. The patient in Case 3 was temporarily given a TLSOby her rehabilitation doctor to assist with pain in the earlypostoperative period. In the patient in Case 5 limited iliacbone for fixation was observed after tumor resection and aTLSO was provided to assist fusion. Inpatient rehabilita-tion was provided as needed. Early mobilization was en-couraged for all patients except for those in whom totalsacrectomy was performed. For these patients bedrest wasordered for 6 to 8 weeks, and they performed nonweight-bearing exercises and subsequently underwent progressiveinclination on a tilt table, prior to working on the parallelbars and eventual ambulation.

Results

Operative and Perioperative Data

Thirteen patients with lumbosacral neoplastic diseaseunderwent resection and spinal–pelvic fixation in whicharthrodesis was performed. In all 13 patients spinal insta-bility secondary to direct tumor invasion and/or iatroge-nic instability was demonstrated after surgery to resect the


Spinal–pelvic fixation for lumbosacral instability

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FIG. 1. Artist’s illustration depicting the posterior exposure of thesacrum, medial ilium, and lumbar spine. The lumbosacral fascia/muscular flap is lifted off of the sacrum and retracted cephalad andlaterally. Inset: The dashed line represents the posterior incision.


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tumor. Five patients required a total sacrectomy (and astaged, anterior then posterior approach) because signifi-cant anterior extension of tumor and/or tumor extensionrostral to the S1–2 level. The median operative time was 8hours and 25 minutes (range 5:46–22:35 hours). Increasedoperative time occurred in patients requiring total sacrecto-my because of its associated extensive tumor resection androtational or free myocutaneous flap closure. Intraoperativeestimated blood loss (median estimated blood loss 2450ml; range 600–16,500 ml) was also expected to be higherin cases of total sacrectomy.

Patients were mobilized as soon as possible except forthose who underwent total sacrectomy. Those in whomsacrectomy was not performed were ambulatory with orwithout assistive devices by a median of 2.5 days postop-eratively (range 1–11 days), as compared with a mediantime of 60 days postoperatively (range 42–90 days) in thosewho underwent total sacrectomy. The median LOS, includ-ing the time spent in the intensive care unit, acute care andin certain cases inpatient rehabilitation, was 9 days for

patients in whom sacrectomy was not performed comparedwith 83 days for those in whom it was. In the patients inwhom total sacrectomy was performed, LOS was consid-erably lengthened because of the more extensive surgeryand its associated increased intensive care unit and acutecare stays, as well as a 54-day average stay in inpatient re-habilitation.

The clinical details and results obtained in the 13 pa-tients with lumbosacral tumors who underwent spinal–pelvic fixation and arthrodesis are summarized in Table 2.Neurological outcome, pain status, ambulatory status, andcomplications are reported hereafter in additional detail.

Neurological Outcome

Preoperatively, neurological compromise was revealedin all 13 patients. Neurological status improved in four pa-tients, three of whom improved one Frankel grade. Twopatients experienced neurological dysfunction followingsurgery (ankle weakness and neurogenic bladder, respec-



FIG. 2. Case 9. Upper Left and Right: Preoperative axial computerized tomography scan (upper left) magnetic resonanceimage (upper right) revealing a sacral chordoma. Lower Left: Hemisection of gross pathological specimen demonstratingcomplete en bloc resection of the sacrum. Lower Center and Right: Postoperative anteroposterior and lateral radiographs.




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FIG. 3. Artist’s illustrations. Upper Left:A 6-mm titanium pilot rod is tapped into thecancellous portion of the ilium to create apath for the contoured rod. This temporaryrod is directed 1.5 cm above the sciatic notchand between the two cortices of the ilium. Itis tapped into place with a mallet to a depthof 6 to 9 cm. Upper Right: A 6-mm titani-um rod is then contoured to match the tem-plate rod (wire) by using tube benders and atable vice. The final shape of spinal-pelvicrod matches template rod (A); tube bendersare used to create the sacroiliac bend ofapproximately 60˚ (B); and the table vice isused to stabilize the sacral and iliac segmentsof the rod while an approximately 110˚ bendis created between the lumbar and sacral seg-ments (C). Lower Left: Illustration of thespinal–pelvic fixation.


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TABLE 2Summary of diagnostic, operative, and postoperative data in 13 patients undergoing spinal–pelvic fixation

Ambulatory Status Case Type of Pain Follow UpNo. Diagnosis Procedure Closure Reduction Preop Postop (mos) Fusion Postop Complications*

1 giant cell sacrectomy, L3–ilium free rectus yes bedridden walker 50 fibrous union severe unilat plantar & dorsiflexionfixation weakness

2 giant cell sacrectomy, L-5 laminectomy, rotational rectus yes independent independent 47 yes seizure, urinary tract infectionL3–ilium fixation

3 renal met S-1 vertebrectomy, L-5 laminec- routine temporary bedridden walker 15 (died) no urinary tract infectiontomy, L3–ilium fixation

4 chordoma sacrectomy, L3–ilium fixation rotational rectus yes independent walker 31 yes small intestinal perforation, sepsis, coagulopathy, Clostridium dificile colitis

5 chordoma instrumentation removal, routine yes walker independent 33 fibrous union noneL2–ilium fixation

6 myxopapillary instrumentation removal, routine yes wheelchair wheelchair 27 yes noneependymoma T7–ilium fixation

7 testicular met instrumentation removal, routine yes wheelchair walker 10 (died) yes noneT11–ilium fixation, 2nd pro-cedure L1–ilium dual fixation

8 spindle cell L5–S1 laminectomy, routine yes cane independent 10 (died) unknown neurogenic bladdersarcoma L4–ilium fixation

9 chordoma sacrectomy L3–ilium fixation B gluteal yes bedridden independent 11 fused unilat Clostridium dificile colitisrotational

10 renal met instrumentation removal, routine yes bedridden independent 9 no meningitis, wound breakdownL2–ilium fixation

11 colon met L4–5 laminectomy, routine no walker walker 3 (died) no admitted 2 wks postdischarge for pneu-L3–ilium fixation monia

12 breast met L5–S1 laminectomy, routine yes bedridden independent 8 partial nonepartial corpectomy S-1,L4–ilium fixation

13 chondrosarcoma sacrectomy, L3–ilium fixation rotational rectus yes independent cane 8 partial urinary tract infection

* Complications that occurred within 30 days postoperatively are listed. Abbreviation: met = metastasis.


tively), which was thought to be related to manipulation ofneural elements during tumor resection rather than the fix-ation process.

Pain Status

All patients in this series presented with lumbosacralpain. Eight patients (62%) rated their preoperative pain assevere, five (38%) as moderate, and two (15%) as mildbased on a VAS. Postoperatively, 11 (85%) of patients ex-perienced significant pain reduction. Of the two patientsin whom significant pain relief was not obtained, onepatient experienced only slight reduction in pain, and theother experienced significant relief for only 6 monthsprior to recurrence of similar severe pain. He eventuallyrequired a myelotomy. The preoperative median VAS was7. This median VAS pain score decreased to 4 at 1-month,3 at 3-months, 2.5 at 6-months, 2 at 1-year, and 2 at lastfollow-up examination (Fig. 4). The reduction in levels ofpain at these five follow-up examinations was found to be statistically significant (exact Wilcoxon’s signed ranksum test). The quantity of total pain medication consump-tion decreased in 10 of 13 patients postoperatively whencompared with preoperative consumption. Pain relief wasfound to be immediate and long lasting.

Ambulatory Status

Ambulatory status (classified as bedridden, wheelchairbound, dependent on a walker or cane, and independent),which is associated with neurological function, spinal–pel-

vic stability, and pain control improved one or more classi-fication levels in eight patients (62%), remained the same inthree patients (23%), and worsened in two patients (15%).One of the patients with worsened ambulatory status is cur-rently using a cane and is likely to be independent in the nearfuture. Five patients who were bedridden preoperatively sec-ondary to pain and lower-extremity weakness became am-bulatory. Individual patient ambulatory status is listed inTable 2.

Perioperative Complications

All adverse events that occurred within 30 days of sur-gery were considered complications. Complications thatrequired additional surgery, caused an increase in LOS, orthose that were potentially life threatening were consideredmajor complications. Complications that did not signifi-cantly change the overall course of events and that did notincrease the LOS were considered minor complications.

Five minor complications occurred in four patients. Onepatient developed a generalized seizure on postoperativeDay 2, which resolved without treatment and did notrequire anticonvulsant medication. This complication wasthought to be secondary to an electrolyte disturbance.Three patients developed urinary tract infections, whichwas not surprising considering the frequency of neurogenicbladders in our patient population. Another patient devel-oped Clostridium dificile-associated colitis.

Five major complications occurred in five patients. Thepatient in Case 1 experienced unilateral ankle plantarflex-



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FIG. 4. Bar graph showing the median VAS pain scores at preoperative evaluation and at postoperative follow-upexaminations. A VAS score of 10 indicates severe pain and a score of 0 indicates no pain. n = number of patients exam-ined at the follow-up interval.


ion and dorsiflexion weakness, which was thought to besecondary to manipulation of the L-5 and S-1 nerve rootsduring resection of recurrent tumor rather than to the fixa-tion process. This weakness has persisted, with minimalimprovement observed postoperatively. The patient in Case4 suffered an initially unrecognized intestinal perforationduring the harvesting and pull through of a rectus myocu-taneous flap closure. This led to sepsis, and the patient wasreturned to the operating room for repair of the injury. Thehardware was not disturbed and was left in place withoutcomplication. The patient in Case 8 developed a neuro-genic bladder that required long-term intermittent catheter-ization following resection of a recurrent spindle cell sar-coma. In the patient in Case 10 development of a woundinfection and meningitis necessitated a return to the operat-ing room for debridement and reclosure of the wound. Nocerebrospinal fluid leak or dural defect was identified onexploration. The patient was given intravenous antibioticmedications in the hospital for 2 weeks and at home for 4weeks. His infection resolved without sequelae, and hispain and neurological status improved. The patient in Case11 was readmitted to the hospital 2 weeks postdischargewith pneumonia, which required a 6-day hospitalizationand intravenous antibiotic medications.

There was one hardware-related complication. This 43-year-old patient with history of testicular cancer that me-

tastasized to the lumbar spine and who had undergonethree previous operations in which fixation and fusion ofL-1 to the sacrum were attempted, was referred to our ser-vice with severe low-back pain. He was found to have LSJinstability with loss of posterior sacral hook fixation. Weused the modified Galveston technique in which L-rodfixation was performed; however, both rods were sub-sequently fractured (Fig. 5 left) at the lumbosacral curve50 days postoperatively. This was repaired using a doublespinal–pelvic rod technique, in which two linked rodswere placed into the ilium bilaterally. These dual linkedrods were attached to lumbar pedicle screws and subse-quently crosslinked (Fig. 5 right). Postoperatively hispain, neurological function, and ambulatory capacity im-proved; however, unfortunately he died 7 months later ofa cocaine overdose.

Discussion

Primary and metastatic neoplasms of the LSJ frequent-ly pose a complex problem for surgical management andstabilization because of anatomy and biomechanical fac-tors of this transition zone between spine and pelvis. Inthis report we describe a safe and effective technique inwhich rigid internal fixation is used to stabilize the spinal–pelvic junction in patients with lumbosacral neoplasms, aswell as the results of such treatment.



FIG. 5. Case 7. Anteroposterior radiographs demonstrating fractured rods (left) and revision in which dual rods wereused for spinal-pelvic fixation (right).


Surgical resection is often considered the best treatmentin cases of primary malignant tumors of the sacrum.15

These tumors are often amenable to complete surgical re-section and cure. Palliation is the goal when metastatictumors of the LSJ are involved. Palliative goals includerestoration of neurological function or prevention of furtherneurological decline, as well as the alleviation of pain.

Pain is the chief complaint of many patients with meta-static spinal disease. In general there are three types ofpain associated with neoplastic spinal involvement: local,radicular, and axial spinal pain. Local pain is usually con-stant and not affected by movement or recumbency, and itis thought to be secondary to periosteal stretching of thespinal structure and by local tumor mass effect. Local painas well as radicular pain can be relieved by resecting thetumor and decompressing the neural elements. Radiationis frequently effective for this type of pain, particularly ifthe tumor is radiosensitive. Axial spinal pain is a mechan-ical pain, which is exacerbated by movement and relievedwith recumbency, that is associated with a structural ab-normality in the spinal column. Spinal stabilization is veryeffective in relieving this type of pain9,16,18 but radiationtherapy is not.

Spinal–pelvic stabilization is often needed in the man-agement of patients with lumbosacral tumors. Variousmethods of lumbosacral fixation exist. These methods canbe classified into three major categories: those requiringsublaminar devices, sacral screw fixation, or iliac rod orscrew fixation.

Sublaminar devices such as hooks, wires, or cables mayprovide a dorsal tension band across the LSJ that can resistflexion. These devices do not provide substantial torsion-al stability or resistance to extension and a fusion rate simi-lar to that achieved in cases in which fusion of the LSJ isperformed without placement of instrumentation has beenfound.23 Because sacral laminae are often thin and/or arefrequently removed in the process of lumbosacral tumorresection, the use of sublaminar devices may be precluded.

The use of sacral pedicle screws provides significantlyincreased rigidity as compared with sublaminar devices.When attached to rods and crosslinked, medially directedscrews create a triangulation effect, which greatly increas-es screw pullout resistance and increases torsional stabili-ty.7,8,20,29 Although lumbosacral pseudarthrosis may be afrequent problem in cases of long, multilevel fixation tothe sacrum,10 sacral screw fixation appears to be sufficientin cases in which the fixation length is short (one or twolevels) and there is minimal instability. In patients harbor-ing neoplasms of the LSJ significant instability secondaryto the destructive process of the tumor is often observed.In addition, the sacral pedicles, body, or alasacralis may beinvolved with the tumor, thereby precluding the use ofsacral screws. In these cases spinal–pelvic fixation withthe modified Galveston technique has proven useful.

The modification refers to the replacement of lumbarsublaminar wiring, as initially described by Allen and Fer-guson,2–5 with pedicle screw fixation to attach the rods tothe lumbar spine segmentally. This is thought to be moresecure than the wiring technique, allowing a shorter fixa-tion length and increased rigidity. Additionally, becausemany of our patients underwent laminectomy for tumorremoval, sublaminar wiring cannot be used. In the modi-

fied technique the rods are contoured and then placed intothe ilium as described4 and are optimally directed 8 to 9cm in depth 1.5 cm above the sciatic notch.22

In biomechanical testing of 10 different lumbosacralfixation techniques in a cadaveric calf model, McCord, etal.,20 have found that rod or screw attachment to the iliumwithstood the greatest load before ultimately failing. Anenhanced degree of fixation was found if purchase anteri-or to the lumbosacral pivot point was achieved. The iliacrod segment in the modified Galveston technique extendsanterior to the lumbosacral pivot point and provides a longlever arm within the ilium to counteract forces exerted bythe lumbar spine. This fixation technique appears to pro-vide the strongest lumbosacral fixation and is especiallyuseful when the LSJ is compromised by tumor. Iliolumbarfixation may be necessary in cases of sacral tumors/resec-tions15 or in cases of sacral agenesis.12

In our series solid bone fusion was achieved in four(31%) and partial or unilateral fusion in three (23%) of pa-tients. In five patients (38%) no convincing evidence offusion on radiographic studies was demonstrated. Becausethree of these five patients have improved clinically, satis-factory fibrous union is suggested. Fusion may not haveoccurred because of the neoplastic disease process and itsassociated catabolism. In addition, a high percentage ofthese patients received radiation therapy (seven patients;54%) and/or chemotherapy (six patients; 46%). All ofthese factors would probably decrease the fusion rate. Thefollow-up periods and/or survival rates were also relative-ly short in three of our patients.

A hardware-related complication occurred in only onepatient (Case 7). The rods fractured bilaterally at the tran-sition between the lumbar and sacral segments. This wascorrected with double iliolumbar rod fixation. Metal fa-tigue in this area of acute angle may be responsible for therod fracture. There have been no other instrumentation-related complications.

Potential drawbacks to this fixation technique includethe relative difficulty of rod contouring and the fixationacross the sacroiliac joint. The three-dimensional rod con-touring technique has been well described by Allen andFerguson3 in a pictorial. We recommend practicing the rod-contouring and -placement techniques in a cadaveric spineprior to actual practice in the operating room. Preformedrods or iliac screws (Isola iliac screws; Acromed, Cleve-land, Ohio) can be obtained, which may decrease intraop-erative time and fiddle-factor, although we have not usedeither of these. Additionally, fixation across the sacroiliacjoint has not been a problem in our series or others.4 Theauthors of cadaveric studies in adults have shown that auto-fusion of this joint occurs in 75% of specimens.6

We have found the surgical treatment of both metastaticand primary neoplasms of the LSJ, followed by the appro-priate stabilization procedure by using the modified Gal-veston technique, to be effective in relieving pain, restoringor preserving neurological function, and restoring ambula-tory capacity. Spine-related pain, as reflected by the VASscore and medication consumption, was significantly re-duced in 85% of our patients. Neurological status improvedin four patients and remained unchanged in seven patients.Ambulatory status improved in 62% (eight patients), re-mained the same in 23% (three patients), and worsened in



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15% (two patients). At last follow-up examination (average20 months postoperatively) 69% of our patients remainedalive.

Conclusions

Surgical resection followed by subsequent stabilization inwhich internal fixation is used is often indicated in the man-agement of patients with primary or metastatic lumbosacralneoplasms. Primary sacral tumors are amenable to completeen bloc resection for possible cure. Palliation is the goal incases of metastatic lumbosacral tumors. In selected patientswith lumbosacral neoplasms, tumor resection followed bymodified Galveston spinal–pelvic fixation is an effectivemeans of stabilization that can provide significant pain re-lief, restore neurological function or prevent further neuro-logical decline, and preserve ambulatory capacity.

Acknowledgments

We thank Dima Abi-said, Ph.D., for statistical assistance and WeiMing Shi, M.D., for imaging support.

Disclosure

The authors have no financial interests in any of the companiesor products described in this paper.

References

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2. Allen BL Jr, Ferguson RL: The Galveston technique for L-rodinstrumentation of the scoliotic spine. Spine 7:276–284, 1982

3. Allen BL Jr, Ferguson RL: A pictorial guide to the GalvestonLRI pelvic fixation technique. Cont Orthop 7:51–61, 1983

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Manuscript received July 30, 1999.Accepted in final form October 6, 1999.Address reprint requests to: Ziya L. Gokaslan M.D., Department

of Neurosurgery, Box 64, The University of Texas M.D. AndersonCancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030.




spinal pelvic fixation in patients with lumbosacral neoplasms · quired spinal–pelvic fixation...

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