SPINE Volume 33, Number 9, pp 940–948 ©2008, …...SPINE Volume 33, Number 9, pp 940–948...

SPINE Volume 33, Number 9, pp 940–948©2008, Lippincott Williams & Wilkins

Full-Endoscopic Cervical Posterior Foraminotomy forthe Operation of Lateral Disc Herniations Using5.9-mm EndoscopesA Prospective, Randomized, Controlled Study

Sebastian Ruetten, MD, PhD,* Martin Komp, MD, PhD,* Harry Merk, MD,†and Georgios Godolias, MD‡

Study Design. Prospective, randomized, controlledstudy of patients with lateral cervical disc herniations,operated either in a full-endoscopic posterior or conven-tional microsurgical anterior technique.

Objective. Comparison of results of cervical discecto-mies in full-endoscopic posterior foraminotomy tech-nique with the conventional microsurgical anterior de-compression and fusion.

Summary of Background Data. Anterior cervical de-compression and fusion is the standard procedure foroperation of cervical disc herniations with radicular armpain. Mobility-preserving posterior foraminotomy is themost common alternative in the case of lateral localiza-tion of the pathology. Despite good clinical results, prob-lems may arise due to traumatization of the access. En-doscopic techniques are considered standard in manyareas, since they may offer advantages in surgical tech-nique and rehabilitation. These days, all disc herniationsof the lumbar spine can be operated in full-endoscopictechnique. With the full-endoscopic posterior cervicalforaminotomy a procedures is available for cervical discoperations.

Methods. One hundred and seventy-five patients withfull-endoscopic posterior or microsurgical anterior cervi-cal discectomy underwent follow-up for 2 years. In addi-tion to general and specific parameters, the followingmeasuring instruments were used: VAS, German versionNorth American Spine Society Instrument, Hilibrand Cri-teria.

Results. After surgery 87.4% of the patients no longerhad arm pain, and 9.2% had occasional pain. The clinicalresults were the same in both groups. There were no sig-nificant difference between the groups in the revision orcomplication rate. The full-endoscopic technique broughtadvantages in operation technique, preserving mobility, re-habilitation, and traumatization.

Conclusion. The recorded results show that the full-endoscopic posterior foraminotomy is a sufficient andsafe supplement and alternative to conventional proce-dures when the indication criteria are fulfilled. At thesame time, it offers the advantages of a minimally inva-sive intervention.

Key words: cervical endoscopic discectomy, cervicalendoscopic nucleotomy, cervical posterior foramin-otomy, cervical disc herniation, cervical foraminal steno-sis, minimally-invasive spine surgery. Spine 2008;33:

940–948

Radicular symptoms with arm pain due to degenerativechanges of the cervical spine arise typically from lateraldisc herniations or osteophytes in the intervertebral fo-ramen. Surgical decompression may become necessary ifconservative therapeutic measures fail, or if there is pa-ralysis. Clinical symptoms were first classified with topo-graphical reference to changes in cervical discs in theearly 1940s.1 In that same period, posterior surgical ac-cess to the cervical spine was developed2,3 which wasmodified over time.4–6 Anterior access for the operationof cervical disc changes was described at the end ofthe1950s.7,8

Anterior cervical decompression and fusion (ACDF)has now developed as a standard procedure in the oper-ation of cervical radiculopathies. It is usually describedas a safe and sufficient procedure with good fusionrates.9–22 Nonetheless, specific problems may occur,such as loss in height of the intervertebral space,23–25

pseudarthroses26 or access complications27,28 Degenera-tion of adjacent segments is discussed as a particulardisadvantage of fusion.29,30 Posterior foraminotomy isthe most common alternative to the ventral proce-dure.6,26,31–47 It is performed without additional stabili-zation and thus preserves the mobility of the segment.The stability does not appear to negatively affected bysurgery.46,48 Disc herniations and stenosis with exclu-sively lateral localization are taken as indications, sincethe cervical myelon must not be mobilized toward medial.49

Access-induced neck pain or intraoperative bleeding maybe a problem.5,38,50–52 No reconstruction of the interver-tebral space can be made.

Modifications to reduce the disadvantages of the ven-tral and dorsal procedures have been described, such asanterior cervical decompression without fusion,53–58 an-terior foraminotomy in various techniques,14,59–67 or

From the *Department of Spine Surgery and Pain Therapy, Center forOrthopaedics and Traumatology, St. Anna-Hospital Herne, Universityof Witten/Herdecke, Herne, Germany; †Clinic for Orthopaedics andOrthopaedic Surgery, Ernst Moritz Arndt University Greifswald, Grei-fswald, Germany; and ‡Center for Orthopaedics and Traumatology,St. Anna-Hospital Herne, University of Witten/Herdecke, Herne, Ger-many.Acknowledgment date: September 6, 2007. Revision date: October 28,2007. Acceptance date: December 3, 2007.The device(s)/drugs is/are FDA-approved or approved by correspond-ing national agency for this indication.No funds were received in support of this work. No benefits in anyform have been or will be received from a commercial party relateddirectly or indirectly to the subject of this manuscript.Address correspondence and reprint requests to Sebastian Ruetten,MD, PhD, Head Department of Spine Surgery and Pain Therapy, Cen-ter for Orthopaedics and Traumatology, St. Anna-Hospital Herne,Hospitalstrasse 19, 44649 Herne, Germany; E-mail: [email protected]

940

posterior microscope-assisted or endoscope-assisted“keyhole foraminotomy.”42,68–72 The cervical disc pros-thesis is intended to combine the advantages of the ven-tral access with the possibilities of total decompressionand reconstruction of the intervertebral space, while pre-serving segment mobility.73–75

Endoscopic techniques are standard procedures in manyareas of medicine. These days, all disc herniations in thelumbar spine can be operated in full-endoscopic tech-nique.76–89 The development of new endoscopes and in-struments enable sufficient bone resection and eliminatetechnical problems.90–92 Anterior, transdiscal endoscopicdecompressions are performed in disc herniations in thecervical spine.93–103 An endoscopic posterior procedurewas cited in 1999 without further specification.104

Although conventional procedures show good results,continuous technical optimization should be the goal.Minimally invasive techniques can reduce traumatiza-tion and its consequences.105,106 The goal for new ormodified procedures is to achieve the clinical results ofestablished standard procedures.107

The objective of this prospective, randomized, con-trolled study was to compare the results of cervical disc-ectomy in lateral disc herniations in full-endoscopic tech-nique via posterior foraminotomy with those of theconventional microsurgical ACDF.

Materials and Methods

Patient CharacteristicsIn the prospective, randomized, controlled study we enrolled200 patients with clinically-symptomatic lateral cervical discherniation who underwent discectomies in 2004/2005. Therewere 132 female and 68 male patients whose age ranged from27 to 62 years (mean, 43 years). The duration of pain rangedfrom 5 days to 8 months (mean, 94 days). One hundred andseventy-one patients had received a mean of 10 weeks conser-vative treatment. The indication for surgery was made due tointolerable radicular pain or neurologic deficits.

Study GroupsOne hundred patients each underwent conventional microsur-gical ACDF, or decompression via full-endoscopic posteriorcervical foraminotomy (FPCF). Randomization was open,since the patients may identify the operation procedure.

Fulfillment of the inclusion criteria for the study and thepresence of the general indication for decompression were de-termined by experienced physicians who were not involved inthe operation. Randomized assignment to the ACDF or FPCFgroup was made by alternation in the order of presentation bynondoctors assisting in the study. All operations were per-formed by 2 surgeons with several years of experience withboth techniques. Eighteen interventions were performed at theC4–C5 level (7 � ACDF, 11 � FPCF), 42 at C5–C6 (22 �ACDF, 20 � FPCF), 116 at C6–C7 (61 � ACDF, 55 � FPCF),and 24 at C7–Th1 (10 � ACDF, 14 � FPCF).

Inclusion CriteriaThe following were the inclusion criteria for discectomy: uni-lateral radiculopathy with arm pain; in MRI/CT lateral or fo-raminal localized monosegmental disc herniation; SegmentsC2–C3–C7–Th1. Cranio-caudal sequestering was not taken as

an exclusion criterion, as long as the lateral localization wasmaintained. Likewise, patients with secondary foraminal ste-nosis were included.

Patients with clear instabilities or deformities were to beexcluded, but there were none in the patient collective. Mediallocalization of the disc herniation was an absolute exclusioncriterion. Patients with isolated neck pain or foraminal stenosiswithout disc herniation were not included in the study.

Operative TechniqueThe conventional microsurgical ACDF was performed inknown standardized technique using a microscope. A PEEK(polyetheretherketone) cage was used as the intervertebral im-plant, there was no additional ventral plating.7,12,13,21,108–111

The FPCF was performed under general anesthesia and ra-diographic control with the patient prone. The cervical spinewas delordosated, the head fixed in place with tape. No frames,like Mayfield clamps, are necessary. The arms are positionedtoward caudal on the body with gentle tension. The FPCF is afull-endoscopic uniportal technique, that means, the workingcanal for the instruments is inside the endoscope, so that noadditional space is needed to insert the instruments, as is thecase in a MED procedure, for example.

The operation is made principally following described con-ventional foraminotomy techniques.5,6 The line of spinal jointsis marked under posterior-anterior radiograph control. Fromthis point on, the operation is performed under lateral radio-graph control. Determination of the segment, performance ofskin incision and blunt insertion of a dilator onto the facetjoint. Insertion of the operation sheath via the dilator; beveledopening. Removal of the dilator. After insertion of the optic,further operation is performed under visual control and con-tinuous fluid flow with 0.9% saline solution. Preparation of thejoint segment and the ligamentum flavum. Start of the forami-notomy by bone resection at the medial joint segments, resec-tion of the lateral ligamentum flavum and identification of thelateral edge of the myelon and branching of the spinal nerves.Bone resection was made under visual control using 3-mmdrills and bone punches, inserted through the intraendoscopicworking canal. Bipolar radiofrequent coagulation of the ve-nous plexus and preparation of the spinal nerve under partic-ular attention to possibly separate motoric and sensory seg-ments. Depending on the pathology in each case, theforaminotomy can be extended toward lateral or cranio-caudal(Figures 1–3).

Figure 1. The intraoperative C-arm control shows the workingsheath with optics and a dissector on the dorsal anulus.

941Full-Endoscopic Cervical Posterior Foraminotomy • Ruetten et al

After all instruments are removed, direct closure of the skin.No drainage is required. All patients are given a soft brace for5 days.

Full-Endoscopic InstrumentsThe rod-lens optics have an outer diameter of 5.9 mm. Theoptics contain an intraendoscopic, eccentric working canalwith 3.1 mm diameter, the light conductor system, a canal forcontinuous intraoperative lavage, and the optical lens system.The angle of vision is 25°. The working sheaths used have anouter diameter of 6.9 mm and a beveled opening, which enablecreation of visual and working fields in an area without clearanatomically-preformed cavity. All of the operating instru-ments and optics were products supplied by WOLF (RichardWolf GmbH, Knittlingen, Germany).

Follow-upFollow-up examinations were conducted at day 1 (200 pa-tients) and at months 3 (191 patients), 6 (187 patients), 12 (184patients) and 24 (175 patients) after surgery. All patients re-ceived the appropriate questionnaire by mail 4 working days inadvance. They came personally to the clinic for follow-up ex-amination. The examinations were performed by 2 physiciansin the clinic, who were not involved in the operations. In addi-tion to general parameters, other information was obtained

using the following instruments: a VAS for neck and arm pain,the German version of the North American Spine Society In-strument,112–114 Hilibrand criteria115,116 based on Smith andRobinson.8 All patients underwent MRI and radiographs afterthe end of the follow-up period.

Statistical AnalysisThe Wilcoxon’s rank sum test and the Mann-Whitney U testwere applied for the comparison of pre- and postoperativeglobal results and comparison of results in the ACDF groupversus the FPCF group at various times. The McNemar test wasused to compare the characteristics of the groups. The descrip-tive assessments and analytical statistics were performed de-pending on the group characteristics with the program packageSPSS. A positive significance level was assumed at probabilityof less than 0.05.

Results

Baseline CharacteristicsOne hundred and seventy-five (88%) (86 � ACDF, 89 �FPCF) patients were included in follow-up after 2 years(84 � ACDF, 91 � FPCF). The remaining cases weredrop outs for the following reasons: 2 patients movedaway and left no forwarding address, 13 patients did notrespond to letters or telephone calls, 10 patients under-went revision surgery with conventional ACDF. The pa-tient population was equal in the ACDF and FPCFgroups. Overall there were no differences in results independence on the individual surgeon.

Intraoperative FindingsFresh nucleus tissue was found in 176 patients (88%). Ofthese, 50 patients additionally presented with osteo-phytes in the foraminal area. In 24 patients (12%), therewas only compression of the nerve due to bulging of theanulus and osteophytic foraminal stenosis. Bony forami-nal stenosis was found in a total of 74 patients (37%).

Ninteen patients (19% of the FPCF group) had a di-vided spinal nerve with separate motoric and sensorysegments. This was only diagnosed in the FPCF group.

Operative TechniqueThe mean operating time in the ACDF group was 68minutes,48–105 and thus significantly shorter (P � 0.001)than in the FPCF group at 28 minutes.19–50 The intra-and postoperative blood loss in the ACDF group, mea-sured by intraoperative suctioning and postoperativedrainage, was less than 10 mL. In the FPCF group, therewas no measurable blood loss. Thanks to the full-endoscopic technique with continuous lavage and thepossibility of radiofrequent, bipolar coagulation there ishardly any bleeding. Postoperative drainage is not nec-essary.

In the ACDF group, the bone harvested intraopera-tively in decompression sufficed to fill the cage in 21cases, Spongiosa was obtained from the pelvis in percu-taneous technique in 79 cases.

Access-related bone resection was necessary in all pa-tients in the FPCF group, bone resection to dilate a fo-raminal stenosis in 39 patients. In the FPCF group there

Figure 2. Intraoperative view at C5/6 with C-6 nerve (long arrow)and free nucleus tissue caudal to the nerve (short arrow).

Figure 3. Intraoperative view after resection of the herniated discand lateral Foramen dilation with cervical myelon (short arrow)and free C-6 nerve (long arrow).

942 Spine • Volume 33 • Number 9 • 2008

was no hindrance due to intraoperative bleeding thanksto continuous fluid flow and the possibility of bipolarpreparation. The full-endoscopic operation was techni-cally feasible in all patients. An intraoperative switch to aconventional procedure was not made in any case.

Perioperative ComplicationsThere were no serious complications in either group,such as postoperative bleeding, hoarseness, injury to thenerve or Dura, damage to the myelon with hemi- or para-paresis or paralysis of the upper extremities.

In the ACDF group, transient difficulty swallowingoccurred in 3 cases, there was 1 surface hematoma and 1case of scar distortion which was cosmetically disruptive.

In the FPCF Group 3 patients (3%) showed transient,dermatoma-related hypesthesia.

There were no further complications, such as infec-tion, spondylodiscitis or thrombosis. Deterioration ofexisting symptoms did not occur in any case.

Recurrences/RevisionsThere were 3 revisions, 1 anterior and 2 posteriorforaminotomies, in the ACDF group due to persistentarm pain. Implant failure occurred in 1 patient, in whomthe ACDF was repeated with tricortical pelvic crest chipand additional ventral dynamic plate. The revision ratein the ACDF group was 4.7%.

In the FPCF Group 3 patients suffered a recurrenceduring the follow-up period after a pain-free interval. Allrecurrences were located lateral and were operated usingthe same technique. The operation time was 27 to 39minutes. 2 patients were operated using conventionalACDF and 1 using FPCF due to persistent pain. Thesebelonged to the group who did not show any free nucleustissue intraoperative. The revision rate in the FPCFgroup was 6.7%.

The difference in the complication rate between the 2groups was not significant.

Radiologic FindingsMRI and radiograph examinations at the end of fol-low-up did not reveal any new damage to adjacent discsin any patient. Nineteen patients showed progradience ofadjacent disc degeneration which had existed preopera-tive.

In the ACDF group, there was no clear radiologicsigns of bony intrusion in the cage without correlation tothe clinical result in 17 (18%) patients. Sintering to max-imum 3 mm was found in 5 (5.8%) patients.

In the FPCF group there were no signs of increasingkyphosis or instability in the operated segment in anypatient. Twenty-one patients (24%) showed signs of ad-vancing degeneration in the disc.

Clinical OutcomeFigure 4 shows the course of arm and neck pain in bothgroups, rated using the VAS scale. There is a significantreduction of radicular pain symptoms. Figure 5 showsthe values of the North American Spine Society Instru-ment Score, which also illustrates equal pain reduction inthe 2 groups. A similar result was obtained in evaluatingthe Hilibrand criteria for the ACDF group in Figure 6and the FPCF group in Figure 7. Overall, the measuringinstruments show constant and significant (P � 0.001)improvement in arm pain and activities of everyday liv-ing in both groups. Figure 8 shows the complete depic-tion of the radicular pain status after 2 years. One hun-dred and fifty-five patients (88.5%) no longer had armpain, 13 (7.5%) occasional pain or clearly reduced painand 7 (4%) no essential improvement. The differences inresults between the groups were not significant. 9 pa-tients (5.1%) suffered progredient neck pain (7 � ACDF,2 � FPCF). Ten patients (5.7%) (4 � ACDF, 6 � FPCF)underwent revision due to persistent arm pain, recur-rences or failure of the implant. Overall, 17 patients(9.7%) had poor results (7 � no essential improvement,

Figure 4. Mean values of VASarm and neck in the ACDF andFPCF group.


10 � revision) (8 � ACDF, 9 � FPCF). One hundred andsixty-four patients (93.7%) reported subjective satisfac-tion and would again undergo the procedure (78 �ACDF � 91%, 86 � FPCF � 96%). Neurologic deficitswere significantly (P � 0.001) reduced when the pa-tient�s history of pain was less than 10 days.

Postoperative pain was significantly reduced in theFPCF group and operation-related neck pain did not re-quire pain medication and lasted maximum 3 days. Mo-bilization was made immediately in both groups depend-ing on the narcosis. Rehabilitative measures were notnecessary except in existing pareses. All results were in-dependent of general parameters, like gender, age,height, weight, occupation or secondary illnesses. Themean postoperative work disability in the FPCF group

was 19 days, versus 34 days in the ACDF group (P �0.01).

Discussion

ACDF is the standard procedure for treatment of cervicalherniated discs.9–22 Posterior foraminotomy is used asthe most common alternative in lateral pathologies, andappears to be gaining in focus with the development ofminimally-invasive techniques.6,26,31– 47 Both proce-dures bring good results when indications are taken intoconsideration. Problems with ACDF may include forexample loss of height in the intervertebral space,pseudarthroses, access complications and adjacent de-generations due to the loss of mobility.23–25,27–30,117 Ac-cess-related neck pain, intraoperative bleeding, a lack of

Figure 5. Mean values of NASSpain and neurology in the ACDFand FPCF group.

Figure 6. Clinical results accord-ing to Hilibrand criteria in theACDF group.


reconstruction of the intervertebral space and the limita-tion of indication to lateral localization are considereddisadvantages of the mobility-preserving posteriorforaminotomy.5,38,46,48–52

The goal of surgery should be sufficient decompres-sion under continuous visualization with concurrentminimization of operation-related trauma and its possi-ble consequences. It was possible to achieve this goal in thelumbar spine by using full-endoscopic techniques.76–84,89–92

Publications on endoscopic operations of the cervicalspine refer to the anterior, transdiscal technique.93–104

Despite technical limitations, good results are described.A posterior full-endoscopic technique has been men-tioned to our knowledge only once in connection with

anterior endoscopy without bone resection and withoutany more precise specification.104

In our study, the clinical results in the ACDF andFPCF group agree with the data in the litera-ture.11,12,15,16,18,19,21,22,26,36–47 Traumatization, operatingtime and rehabilitation time are reduced compared toconventional procedures.12,16,18,19,22,26,40–47,118 No op-eration-induced neck pain or instabilities occurred. Nopatient suffered deterioration of existing symptoms,which corresponds to experience with a minimally-invasive epidural and intervertebral procedure in thelumbar spine.119–122 A significant and constant improve-ment was achieved in both groups without significantdifferences.

Figure 7. Clinical results accord-ing to Hilibrand criteria in theFPCF group.

Figure 8. Clinical results in per-cent in the ACDF and FPCFgroup.


The recurrence rate in the FPCF group of 3.4% iswithin the results published for the standard foramin-otomy.35,42,44,118 Revisions could be performed with ap-propriate indication using the same full-endoscopic tech-nique. Negative effects due to opening of the anulus arediscussed in connection with the lumbar spine.121,123–125

Unlike ACDF, real recurrences can never be totally ruledout.

The rate of complications and revisions in the ACDFgroup is comparable to published results and lower thanfor conventional foraminotomies in the FPCFgroup.11,12,15,16,18,19,21,22,26,35–47,118 The differences be-tween the groups are not significant.

The FPCF was technically feasible in all cases. Surgeryunder continuous fluid flow is known to reduce intraop-erative bleeding and enables very good vision in combi-nation with the 25° optics.80–83,89–92 In combinationwith the possibility of radiofrequent, bipolar coagula-tion, this appears to reduce especially the epidural bleed-ing, which may be problematical in posterior procedures.Bone resection is required for access and usually neces-sary in foraminal stenosis. This applies for all direct de-compression techniques which do not reconstruct theintervertebral space and can achieve indirect dilation ofthe Foramen via distraction. Thus, the possibility of boneresection is prerequisite to sufficient full-endoscopic de-compression. This could be achieved in recent years thanksto further technical developments.83,90–92 For this reason,results of older studies are almost incomparable to today’sstudies.104 Since the myelon may not be manipulated, pos-terior decompression can only be performed in lateral lo-calization of the pathology.5,38,46,48–52 This applies tomany cases with radicular pain due to disc herniation. Wecannot agree without reservation to the statement that onlyindirect decompression is possible by means of posteriorforaminotomy.49 Removal of nucleus material or dilationof the foramen corresponds to direct decompression. Indi-rect decompression occurs only in purely ventral compres-sion due to hard tissue. The same problem may arise inACDF with dorsal foraminal stenosis. Unlike in anteriorprocedures, cranial and caudal dislocated sequester in lat-eral localization can be resected under direct vision fromdorsal. Given appropriate indication, revisions can be per-formed using the same technique. Revision by means ofACDF is not made more difficult by prior operation.

The present prospective study shows that predictablesufficient decompression in lateral disc herniations canbe achieved by full-endoscopic posterior foraminotomyunder continuous visualization in a short operation time.The clinical results of conventional procedures areachieved, while advantages of a minimally invasive pro-cedure are given. We consider the technique described tobe a sufficient and safe supplement within the spectrumof conventional procedures.

Comparison of the 2 techniques and comparison withthe literature shows, in our opinion, the following ad-vantages for FPCF: facilitation for the surgeon by excel-lent presentation of the anatomic structures, good illu-

mination and expanded field of vision thanks to the 25°optics; economical procedure thanks to short operationtime, rapid rehabilitation and low postoperative costs ofcare; reduced traumatization, no operation-related neckpain; reduced bleeding; reduced risk of access-relatedcomplications; maintained mobility; facilitated revisionoperations; monitor image as the basis for training ofassistants; high patient acceptance. The following mustbe considered disadvantages: limited possibility to ex-pand the operation in the event of unforeseen hin-drances; indication limited to lateral localization of thepathology; no reconstruction of the intervertebral space;no direct decompression in ventrally-caused stenosis;high learning curve.

Key Points

● The clinical results of the full-endoscopic poste-rior cervical foraminotomy are equal to those ofthe conventional microsurgical anterior decom-pression and fusion. At the same time, there areadvantages in the operation technique and reducedtraumatization.● Indications for the full-endoscopic posterior cer-vical foraminotomy are radicular arm pain due tolateral disc herniation.● The full-endoscopic technique is a sufficient andsafe supplement and alternative to conventionalmicrosurgical procedures.● Open and maximally-invasive procedures arenecessary in spinal surgery and must be masteredby surgeons so that they also overcome problemsand complications encountered when performingfull-endoscopic procedures.

References

1. Abumi K, Panjabi MM, Kramer KM, et al. Biomechanical evaluation oflumbar spinal stability after graded facetectomies. Spine 1990;15:1142–7.

2. Brayda-Bruno M, Cinnella P. Posterior endoscopic discectomy (and otherprocedures). Eur Spine J 2000;9:24–9.

3. Mixter WJ, Barr JS. Rupture of the intervertebral disc with involvement ofthe spinal canal. N Engl J Med 1934;211:205–10.

4. Putti V. Pathogenesis of sciatic pain. Lancet 1927;2:53.5. Steinke CR. Spinal tumors: statistics on a series of 330 collected cases.

J Nerv Ment Dis 1918;47:418–26.6. Stookey B. Compression of spinal cord due to ventral extradural chondro-

mas:diagnosis and surgical treatment. Arch Neurol Psychiatry 1928;20:275–91.

7. Hult L. Retroperitoneal disc fenestration in low back pain and sciata. ActaOrthop Scand 1956;20:342–8.

8. Valls J, Ottolenghi CE, Schajowicz F. Aspiration biopsy in diagnosis oflesions of vertebral bodies. JAMA 1948;136:376.

9. Caspar W. A new surgical procedure for lumbar disc herniation causing lesstissue damaging through a microsurgical approach. In: Wullenweber R,Brock M, eds. Advances in Neurosurgery 1977;7:74–7.

10. Gottlob C, Kopchok G, Peng SH, et al. Holmium:YAG laser ablation ofhuman intervertebral disc: preliminary evaluation. Lasers Surg Med 1992;12:86–91.

11. Hijikata S. Percutaneous dicectomy: a new treatment method for lumbardisc herniation. J Toden Hosp 1975;5:5–13.

12. Kambin P, Gellman H. Percutaneous lateral discectomy of the lumbarspine: a preliminary report. Clin Orthop 1983;174:127–32.

13. Maroon JC, Onik G, Sternau L. Percutaneous automated discectomy: a newapproach to lumbar surgery. Clin Orthop 1989;238:64–70.


14. Smith L, Garvin PJ, Gesler RM, et al. Enzyme dissolution of the annuluspulposus. Nature 1963;198:1311–2.

15. Goald HJ. Microlumbar discectomy–follow-up of 147 patients. Spine1978;3:183–5.

16. Goald HJ. Microlumbar discectomy: follow-up of 477 patients. J Micro-surg 1981;2:95–100.

17. Wilson DH, Kenning J. Microsurgical lumbar discectomy: preliminary re-port of 83 consecutive cases. Neurosurgery 1979;42:137–40.

18. Forst R, Hausmann G. Nucleoscopy: a new examination technique. ArchOrthop Trauma Surg 1983;101:219–21.

19. Kambin P, Casey K, O‘Brien E, et al. Transforaminal arthroscopic decom-pression of the lateral recess stenosis. J Neurosurg 1996;84:462–67.

20. Kambin P, O‘Brien E, Zhou L, et al. Arthroscopic microdiscectomy andselective fragmentectomy. Clin Orthop 1998;347:150–67.

21. Kambin P, Sampson S. Posterolateral percutaneous suction-excision of her-niated lumbar intervertebral discs: report of interim results. Clin Orthop1986;207:37–43.

22. Kambin P, Zhou L. History and current status of percutaneous arthroscopicdisc surgery. Spine 1996;21:57–61.

23. Kambin P. Arthroscopic Microdiscectomy. Baltimore, Urban & Schwar-zenberg; 1991.

24. Knight MT, Vajda A, Jakab GV, et al. Endoscopic laser foraminoplasty onthe lumbar spine–early experience. Minim Invasive Neurosurg 1998;41:5–9.

25. Lee SH, Lee SJ, Park KH, et al. Comparison of percutaneous manual andendoscopic laser discectomy with chemonucleolysis and automated nucle-otomy. Orthopade 1996;25:49–55.

26. Lew SM, Mehalic TF, Fagone KL. Transforaminal percutaneous endo-scopic discectomy in the treatment of far-lateral and foraminal lumbar discherniations. J Neurosurg 2001;94:216–20.

27. Mathews HH. Transforaminal endoscopic microdiscectomy. NeurosurgClin North Am 1996;7:59–63.

28. Mayer HM, Brock M. Percutaneous endoscopic discectomy: surgical tech-nique and preliminary results compared to microsurgical discectomy.J Neurosurg 1993;78:261.

29. Savitz MH. Same-day microsurgical arthroscopic lateral-approach laser-assisted (SMALL) fluoroscopic disectomy. J Neurosurg 1994;80:1039–45.

30. Siebert W. Percutaneous nucleotomy procedures in lumbar intervertebraldisk displacement. Orthopade 1999;28:598–608.

31. Stucker R. The transforaminal endoscopic approach. In: Mayer HM, ed.Minimally Invasive Spine Surgery. Berlin, Heidelberg, New York: Springer;2000:201–6.

32. Tsou PM, Yeung AT. Transforaminal endoscopic decompression for radic-ulopathy secondary to intracanal noncontained lumbar disc herniations:outcome and technique. Spine J 2002;2:41–8.

33. Yeung AT, Yeung CA. Advances in endoscopic disc and spine surgery:foraminal approach. Surg Technol Int 2003;11:255–63.

34. Yeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar discherniation: surgical technique, outcome and complications in 307 consec-utive cases. Spine 2002;27:722–31.

35. Destandau J. A special device for endoscopic surgery of lumbar disc herni-ation. Neurol Res 1999;21:39–42.

36. Nakagawa H, Kamimura M, Uchiyama S, et al. Microendoscopic discec-tomy (MED) for lumbar disc prolapse. J Clin Neurosci 2003;10:231–5.

37. Perez-Cruet MJ, Foley KT, Isaacs RE, et al. Microendoscopic lumbar disc-ectomy: technical note. Neurosurgery 2002;51:129–36.

38. Schick U, Doehnert J, Richter A, et al. Microendoscopic lumbar discectomyversus open surgery: an intraoperative EMG study. Eur Spine 2002;11:20–6.

39. Ruetten S, Komp M, Godolias G. An extreme lateral access for the surgeryof lumbar disc herniations inside the spinal canal using the full-endoscopicuniportal transforaminal approach. – technique and prospective results of463 patients. Spine 2005;30:2570–8.

40. Ruetten S, Komp M, Godolias G. A new full-endoscopic technique for theinterlaminar operation of lumbar disc herniations using 6 mm endoscopes:prospective 2-year results of 331 patients. Minim Invasive Neurosurg 2006;49:80–7.

41. Ruetten S, Komp M, Godolias G. Full-endoscopic interlaminar operation oflumbar disc herniations using new endoscopes and instruments. OrthopPraxis 2005;10:527–32.

42. Ruetten S. The full-endoscopic interlaminar approach for lumbar disc her-niations. In: Mayer HM, ed. Minimally Invasive Spine Surgery. Berlin,Heidelberg, New York: Springer; 2005:346–355.

43. Annerzt M, Jonsson B, Stromqvist B, et al. No relationship between epi-dural fibrosis and sciatica in the lumbar postdiscectomy syndrome. A studywith contrast-enhanced magnetic resonance imaging in symptomatic andasymptomatic patients. Spine 1995;20:449–53.

44. Ebeling U, Reichenberg W, Reulen HJ. Results of microsurgical lumbardiscectomy. Review of 485 patients. Acta Neurochir 1986;81:45–52.

45. Ferrer E, Garcia-Bach M, Lopez L, et al. Lumbar microdiscectomy: analysisof 100 consecutive cases. Its pitfalls and final results. Acta Neurochir Suppl1988;43:39–43.

46. Hermantin FU, Peters T, Quartarato LA. A prospective, randomizedstudycomparing the resultsof open discectomy with those of video-assisted ar-throscopic microdiscectomy. J Bone Joint Surg 1999;81:958–65.

47. Kotilainen E, Valtonen S. Clinical instability of the lumbar spine after mi-crodiscectomy. Acta Neurochir 1993;125:120–6.

48. McCulloch JA. Principles of Microsurgery for Lumbar Disc Diseases. NY:Raven Press; 1989.

49. Nystrom B. Experience of microsurgical compared with conventional tech-nique in lumbar disc operations. Acta Neurol Scand 1987;76:129–41.

50. Williams RW. Microlumbar discectomy. A 12-year statistical review. Spine1986;11:851–2.

51. Fritsch EW, Heisel J, Rupp S. The failed back surgery syndrome: reasons,intraoperative findings and long term results: a report of 182 operativetreatments. Spine 1996;21:626–33.

52. Kraemer J. Intervertebral Disk Diseases. Stuttgart: Thieme; 1990.53. Lewis PJ, Weir BKA, Broad RW, et al. Longterm prospective study of

lumbosacral discectomy. J Neurosurg 1987;67:49–54.54. Ruetten S, Komp M, Godolias G. Spinal cord stimulation using an 8-pole

electrode and double-electrode system as minimally invasive therapy of thepost-discotomy and post-fusion syndrome. Z Orthop 2002;140:626–31.

55. Schoeggl A, Maier H, Saringer W, et al. Outcome after chronic sciatica asthe only reason for lumbar microdiscectomy. J Spinal Disord Tech 2002;15:415–9.

56. Ruetten S, Meyer O, Godolias G. Epiduroscopic diagnosis and treatment ofepidural adhesions in chronic back pain syndrome of patients with previoussurgical treatment: first results of 31 interventions. Z Orthop 2002;140:171–5.

57. Haher TR, O’Brien M, Dryer JW, et al. The role of the lumbar facet jointsin spinal stability. Identification of alternative paths of loading. Spine 1994;19:2667–70.

58. Hopp E, Tsou PM. Postdecompression lumbar instability. Clin Orthop1988;227:143–51.

59. Kaigle AM, Holm SH, Hansson TH. Experimental instability in the lumbarspine. Spine 1995;20:421–30.

60. Kato Y, Panjabi MM, Nibu K. Biomechanical study of lumbar spinal sta-bility after osteoplastic laminectomy. J Spinal Disord 1998;11:146–50.

61. Kotilainen E. Clinical instability of the lumbar spine after microdiscectomy.In: Gerber BE, Knight M, Siebert WE, eds. Lasers in the MusculoskeletalSystem. Berlin, Heidelberg, New York: Springer; 2001:241–3.

62. Sharma M, Langrana NA, Rodrigues J. Role of ligaments and facets inlumbar spinal stability. Spine 1995;20:887–900.

63. Cooper R, Mitchell W, Illimgworth K, et al. The role of epidural fibrosisand defective fibrinolysis in the persistence of postlaminectomy back pain.Spine 1991;16:1044–8.

64. Waddell G, Reilly S, Torsney B, et al. Assessment of the outcome of lowback surgery. J Bone Joint Surg Br 1988;70:723–7.

65. Hedtmann A. The so-called post-discotomy syndrome – failure of interver-tebral disc surgery? Z Orthop 1992;130:456–66.

66. Kim SS, Michelsen CB. Revision surgery for failed back surgery syndrome.Spine 1992;17:957–60.

67. Parke WW. The significance of venous return in ischemic radiculopathy andmyelopathy. Orhop Clin North Am 1991;22:213–20.

68. Weber BR, Grob D, Dvorak J, et al. Posterior surgical approach to thelumbar spine and its effect on the multifidus muscle. Spine 1997;22:1765–72.

69. Devulder J, De Laat M, Van Batselaere M, et al. Spinal cord stimulation: avaluable treatment for chronic failed back surgery patients. J Pain SymptomManage 1997;13:296–301.

70. Rainov NG, Heidecke V, Burkert W. Short test-period spinal cord stimu-lation for failed back surgery syndrome. Minim Invasive Neurosurg 1996;39:41–4.

71. Maroon JC. Current concepts in minimally invasive discectomy. Neurosur-gery 2002;51:137–45.

72. Chiu JC, Clifford T, Princenthal R, et al. Junctional disc herniation syn-drome in post spinal fusion treated with endoscopic spine surgery. SurgTechnol Int 2005;14:305–15.

73. Epstein J, Adler R. Laser-assisted percutaneous endoscopic neurolysis. PainPhysician 2000;3:43–5.

74. Ruetten S, Godolias G. Possibilities of epiduroscopy in the treatment ofchronic back pain syndrome using holmium laser and instruments–Firstresults of 53 patients having had no previous surgical treatment. OrthopPraxis 2002;38:315–8.


75. Ruetten S, Meyer O, Godolias G. Application of holmium:YAG laser inepiduroscopy: extended practicabilities in the treatment of chronic backpain syndrome. J Clin Laser Med Surg 2002;20:203–6.

76. Jang JS, An SH, Lee SH. Transforaminal percutaneous endoscopic discec-tomy in the treatment of foraminal and extraforaminal lumbar disc hernia-tions. J Spinal Disord Tech 2006;19:338–43.

77. Adson AW, Ott WO. Results of the removal of tumors of the spinal cord.Arch Neurol Psychiatry 1922;8:520–38.

78. Yeung AT. Minimally invasive disc surgery with the Yeung EndoscopicSpine System (YESS). Surg Technol Int 2000;8:267–77.

79. Yeung AT. The evolution of percutaneous spinal endoscopy and discec-tomy: state of the art. Mt Sinai J Med 2000;67:327–32.

80. Choi G, Lee SH, Raiturker PP, et al. Percutaneous endoscopic interlaminardiscectomy for intracanalicular disc herniations at L5–S1 using a rigidworking channel endoscope. Neurosurgery 2006;58(Suppl 1):S59–S68.

81. Lee SH, Kang BU, Ahn Y, et al. Operative failure of percutaneous endo-scopic lumbar discectomy: a radiologic analysis of 55 cases. Spine 2006;31:285–90.

82. Schubert M, Hoogland T. Endoscopic transforaminal nucleotomy withforaminoplasty for lumbar disc herniation. Oper Orthop Traumatol 2005;17:641–61.

83. Andersson GBJ, Brown MD, Dvorak J, et al. Consensus summary on thediagnosis and treatment of lumbar disc herniation. Spine 1996;21:75–8.

84. McCulloch JA. Focus issue on lumbar disc herniation: macro- and micro-discectomy. Spine 1996;21:45–56.

85. Ruetten S, Komp M, Merk H, et al. Use of newly developed instruments andendoscopes: full-endoscopic resection of lumbar disc herniations via theinterlaminar and lateral transforaminal approach. J Neurosurg Spine 2007;6:521–30.

86. Ruetten S, Komp M, Godolias G. New developed devices for the full-endoscopic lateral transforaminal operation of lumbar disc herniations.WSJ 2006;3:157–65.

87. Ruetten S, Komp M, Godolias G. Lumbar discectomy with the full-endoscopic interlaminar approach using new developed optical systems andinstruments. WSJ 2006;3:148–56.

88. Daltroy LH, Cats-Baril WL, Katz JN, et al. The North American SpineSociety (NASS) lumbar spine outcome instrument: releability and validitytests. Spine 1996;21:741–9.

89. Pose B, Sangha O, Peters A, et al. Validation of the North American spinesociety instrument for assessment of health status in patients with chronicbackache. Z Orthop 1999;137:437–41.

90. Fairbank JCT, Couper J, Davies JB, et al. The Oswestry low back painquestionnaire. Physiotherapy 1980;66:271–3.

91. Ahn Y, Lee SH, Park WM, et al. Percutaneous endoscopic lumbar discec-tomy for recurrent disc herniation: surgical technique, outcome and prog-nostic factors of 43 consecutive cases. Spine 2004;29:326–32.

92. Lee SH, Kim SK, Ahn Y, et al. The preoperative radiological findings thataffect the clinical outcomes after percutaneous endoscopic lumbar discec-tomy. WSJ 2006;1:133–40.

93. Hoogland T, Schubert M, Miklitz B, et al. Transforaminal posterolateralendoscopic discectomy with or without the combination of a low-dosechymopapain: a prospective randomized study in 280 consecutive cases.Spine 2006;24:890–7.

94. Mariconda M, Galasso O, Secondulfo V, et al. Minimum 25-year outcomeand functional assessment of lumbar discectomy. Spine 2006;31:2593–9.

95. Andrews DW, Lavyne MH. Retrospective analysis of microsurgical andstandard lumbar discectomy. Spine 1990;15:329–35.

96. Mayer HM, Brock M. Percutaneous endoscopic discectomy: surgical tech-nique and preliminary results compared to microsurgical discectomy.J Neurosurg 1993;78:216–25.

97. Schreiber A, Suezawa Y, Leu H. Does percutaneous nucleotomy with dis-coscopy replace conventional discectomy? Eight years of experience andresults in treatment of herniated lumbar disc. Clin Orthop Relat Res 1989;238:35–42.

98. Lee SH, Chung SE, Ahn Y, et al. Comparative radiologic evaluation ofpercutaneous endoscopic lumbar discectomy and open microdiscectomy: amatched cohort analysis. Mt Sinai J Med 2006;73:795–801.

99. Schmid UD. Microsurgery of lumbar disc prolapse. Superior results of mi-crosurgery as compared to standard- and percutaneous procedures (reviewof literature). Nervenarzt 2000;71:265–74.

100. Ebara S, Harada T, Hosono N, et al. Intraoperative measurement of lumbarspinal instability. Spine 1992;17:44–50.

101. Faulhauer K, Manicke C. Fragment excision versus conventional disc re-moval in the microsurgical treatment of herniated lumbar disc. Acta Neu-rochir 1995;133:107–11.

102. Goel VK, Nishiyama K, Weinstein JN, et al. Mechanical properties oflumbar spinal motion segments as affected by partial disc removal. Spine1986;11:1008–12.

103. Iida Y, Kataoka O, Sho T, et al. Postoperative lumbar spinal instability occur-ring or progressing secondary to laminectomy. Spine 1990;15:1186–9.

104. Johnsson KE, Redlund-Johnell I, Uden A, et al. Preoperative and postoper-ative instability in lumbar spinal stenosis. Spine 1989;14:591–3.

105. Kambin P, Cohen L, Brooks ML, et al. Development of degenerative spon-dylosis of the lumbar spine after partial discectomy: comparison of lamin-otomy, discectomy and posterolateral discectomy. Spine 1994;20:599–7.

106. Mochida J, Toh E, Nomura T. The risks and benefits of percutaneousnucleotomy for lumbar disc herniation. A 10-year longitudinal study.J Bone Joint Surg Br 2001;83:501–5.

107. Natarajan RN, Andersson GB, Padwardhan AG, et al. Study on effect ofgraded facetectomy on change in lumbar motion segment torsional flexi-bility using three-dimensional continuum contact representation for facetjoints. J Biomech Eng 1999;121:215–21.

108. Celik SE, Kara A, Celik S. A comparison of changes over time in cervicalforaminal hight after tricortical iliac graft or polyetheretherketone cageplacement following anterior discectomy. J Neurosurg Spine 2007;6:10–6.

109. Samartzis D, Shen FH, Lyon C, et al. Does rigid instrumentation increasethe fusion rate in one-level anterior cervical discectomy and fusion? Spine J2004;4:636–43.

110. Boakye M, Mummaneni PV, Garrett M, et al. Anterior cervical discectomyand fusion involving a polyetheretherketone spacer and bone morphoge-netic proteine. J Neurosurg Spine 2005;2:521–5.

111. Liao JC, Niu CC, Chen WJ, et al. Polyetheretherketone (PEEK) cage filledwith cancellous allograft in anterior cervical discectomy and fusion. IntOrthop 2007; [Epub ahead of print].

112. Ross JS, Robertson JT, Frederickson RC, et al. Association between peri-dural scar and recurrent radicular pain after lumbar discectomy: magneticresonance evaluation. Neurosurgery 1996;38:861–3.

113. Zander T, Rohlmann A, Kloeckner C, et al. Influence of graded facetectomyand laminectomy on spinal biomechanics. Eur Spine J 2003;12:427–34.

114. Balderston RA, Gilyard GG, Jones AM, et al. The treatment of lumbar discherniation: simple fragment excision versus disc space curettage. J SpinalDisord 1991;4:22–5.

115. Bucy PC. Chondroma of intervertebral disc. JAMA 1930;94:1552.116. Caspar W, Campbell B, Barbier DD, et al. The Caspar microsurgical disc-

ectomy and comparison with a conventional standard lumbar disc proce-dure. Neurosurgery 1991;28:78–87.

117. Donceel P, Du Bois M. Fitness for work after lumbar disc herniation: aretrospective study. Eur Spine 1998;7:29–35.

118. Mayer HM. The microsurgical interlaminar, paramedian approach. In:Mayer HM, ed. Minimally Invasive Spine Surgery. Berlin, Heidelberg, NewYork: Springer; 2000:79–91.

119. Mochida J, Nishimura K, Nomura T, et al. The importance of preservingdisc structure in surgical approaches to lumbar disc herniation. Spine 1996;21:1556–64.

120. Ramirez LF, Thisted R. Complications and demographic characteristics ofpatients undergoing lumbar discectomy in community hospitals. Neurosur-gery 1989;25:226–31.

121. Rantanen J, Hurme M, Falck B, et al. The lumbar multifidus muscle fiveyear after surgery for a lumbar intervertebral disc herniation. Spine 1993;18:568–74.

122. Rompe JD, Eysel P, Zollner J, et al. Intra- and postoperative risk analysisafter lumbar intervertebral disk operation. Z Orthop 1999;137:201–5.

123. Stolke D, Sollmann WP, Seifert V. Intra- and postoperative complicationsin lumbar disc surgery. Spine 1989;14:56–9.

124. Wildfoerster U. Intraoperative complications in lumbar intervertebral discoperations. Cooperative study of the spinal study group of the GermanSociety of Neurosurgery. Neurochirurgica 1991;34:53–6.

125. Aydin Y, Ziyal IM, Dumam H, et al. Clinical and radiological results of lumbarmicrodiscectomy technique with preserving of Ligamentum flavum comparingto the standard microdiscectomy technique. Surg Neurol 2002;57:5–13.


SPINE Volume 33, Number 9, pp 940–948 ©2008, …...SPINE Volume 33, Number 9, pp 940–948...

Documents

Transcript of SPINE Volume 33, Number 9, pp 940–948 ©2008, …...SPINE Volume 33, Number 9, pp 940–948...