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Design of Lamifuse: a randomised, multi-centre controlled trial comparing laminectomy without or with dorsal fusion for cervical myeloradiculopathy

Design of Lamifuse: a randomised, multi-centre controlled trial comparing laminectomy without or... Background: laminectomy is a valuable surgical treatment for some patients with a cervical radiculomyelopathy due to cervical spinal stenosis. More recently attention has been given to motion of the spinal cord over spondylotic spurs as a cause of myelopathic changes. Immobilisation by fusion could have a positive effect on the recovery of myelopathic signs or changes. This has never been investigated in a prospective, randomised trial. Lamifuse is an acronyme for laminectomy and fusion. Methods/Design: Lamifuse is a multicentre, randomised controlled trial comparing laminectomy with and without fusion in patients with a symptomatic cervical canal stenosis. The study population will be enrolled from patients that are 60 years or older with myelopathic signs and/or symptoms due to a cervical canal stenosis. A kyphotis shape of the cervical spine is an exclusion criterium. Each treatment arm needs 30 patients. Discussion: This study will contribute to the discussion whether additional fusion after a cervical laminectomy results in a better clinical outcome. ISRCT number: ISRCTN72800446 sometimes instability occurs. This may lead to a stenosis Background Cervical spondylosis is a progressive degenerative disease of the cervical spinal canal. In most instances it will of the spine. As people grow older, the prevalence of cer- remain asymptomatic. However, in some persons the ste- vical spondylosis increases. It is a natural process of aging. nosis of the spinal canal leads to a compression of the spi- Cervical spondylosis is seen in 10% of individuals in the nal cord. It is important to realize that not only static age of 25 years, whereas in 95% of the persons of 65 years compression leads to neurological symptoms, but also [1]. dynamic factors do. In a normal situation the spinal cord will move during flexion and extension. Ventral osteo- Due to the degenerative process reduction of height of the phytes in the spinal canal prevent up – and downward intervertebral discs, formation of spondylophytes and movement [1]. Furthermore, the spinal cord is more Page 1 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 stretched over the anterior bars increasing axial tension Methods/Design within the spinal cord. These forces are multidirectional Hypothesis Patients that are surgically treated for signs and symptoms creating secondary shearing forces resulting in stretch and shear injury to myelin and neural elements [2-4]. due to a stenosis of the cervical spinal canal have a better clinical outcome when a dorsal fusion is performed in Patients may present with a diversity of well known signs addition to a laminectomy compared to those that have and symptoms with variable intensities. Disturbance of solely a laminectomy. the sensibility in the arms, clumsiness of the hands and problems with micturation may occur. However, the hall- At the end of the study, the quality of life, complications, mark symptoms are gait abnormalities, weakness of the and the costs will be evaluated comparing these two treat- legs or stiffness of the legs [1,5]. ment groups. The natural course of the cervical myelopathy is variable. In – and exclusion criteria But patients developing mild or moderate symptoms are Patients with a minimal age of 60 years are included less likely to improve spontaneously. Non operative treat- (Table 1). At neurologic examination myelopathic ment will mainly affect neck pain or accompanying radic- changes must be apparent. At magnetic resonance imag- ulopathy. Improvement has been noted but is variable ing, concordant stenotic alterations at the cervical level(s) [6,7]. Patients with myelopathic signs and symptoms will, must be present. At the plain sitting lateral radiograph a however, likely benefit from surgery [5,7,8]. lordotic spine must be shown. The shape of the cervical spine is lordotic when the vertebral bodies of C3 to C6 are Surgical approaches for cervical myelopathy due to cervi- in front of a line drawn from a point of the posterior infe- cal spondylosis can be anterior, posterior or combined. rior part of the vertebral body of C2 to a point at the pos- The last option is reserved for deformity correction. In terior superior part of the vertebral body of C7 (Figure 1). most instances a lordotic or slight kyphotic cervical spine is present. The choice for an anterior or posterior Only patients that sign the informed consent after some approach is dependent on the main site of compression, time of reflection (1 week) are included. the shape of the cervical sagittal curvature and to a lesser account on the preference of the surgeon. Clinical evaluation and follow up At the first intake, duration of symptoms, other diseases, Dorsal approaches are laminectomy or laminoplasty. A severity of signs and symptoms are noted. Neurologic difference in clinical outcome has never been established. examination is performed by an independent neurologist. Prevention of post – laminectomy kyphosis is a reason for At follow up, the severity of signs and symptoms are also laminoplasty. If an additional, instrumented dorsal noted. Special attention is given to the myelopathic fusion is performed, the change of developing a post-sur- gical kyphosis is nearly zero[9]. It should be memorized that spondylotic processes also generate reduced motion of the spinal segments, a natural course [1]. From this point of view, decompression with fusion will have better clinical results when compared to decompression solely. In literature, indications in this direction are found. Fre- quently used dorsal fusion techniques today use lateral mass screws and cervical pedicle screws. This is relatively safe with a minimal persistent complication rate. Further- more, in experienced hands these techniques do not add substantial time to the duration of the surgery [7,9]. Despite a long-lasting interest in the various techniques, the clinical superiority of one method over the other has never been established. To our knowledge, a randomized controlled trial comparing laminectomy with or without Li C2 to the posterior superior p C7 in kyphotic cervical curve (B) Figure 1 ne fr case of om the p a normal cervical osterior inferioralordotic curv rt o f part of the vertebral body of the verteb ature (A ral body of ) and a fusion has never been performed. Line from the posterior inferior part of the vertebral body of C2 to the posterior superior part o f the vertebral body of C7 in case of a normal cervical lordotic curvature (A) and a kyphotic cervical curve (B). Page 2 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 Table 1: in – and exclusioncriteria cranial laminectomy level to at least one level below the most caudal planned laminectomy site. If the lowest level Inclusion Exclusion of fusion would include C7 or lower extension of the fusion to the upper thoracic spine (Th2 or Th3) is recom- 60 years or older Previous cervical surgery for mended[11]. This extension of the fusion is thought to myelopathic signs and symptoms Cervical myelopathic Solely radiculopathy, or most prevent junction disease at the cervicothoracic junction. symptoms and or signs at important complaint For example, if the laminectomy includes the levels C4 to neurologic examination C6, the fusion would be from C3 to C7. Because C7 is the Stenosis of cervical spinal canal Unable to undergo MRI lowest fusion level, incorporation of Th1 is recom- at MRI mended. Lordotic shape at lateral Life expectancy less than 2 years cervical plain radiograph, or at lateral cervical radiograph in Surgical demands extension Since fusion is added, only centres with a known spinal Informed consent Other diseases interfering with surgical experience are asked to participate. The surgeons neurologic symptoms and signs, for example spinal cord glioma, thoracic performing a laminectomy should also be experienced in herniated disc with spinal cord lateral mass fixation techniques, especially lateral mass compression, multiple sclerosis etc. and cervical pedicle screws. Rheumatoid arthritis Trauma to the neck in history Study Sites Diseases interfering with rehabilitation, for example severe The following centres will paricipate: Radboud University cardiac congestive disease. Nijmegen Medical Centre, Nijmegen; Canisius Wil- Participation in another study helmina Hospital, Nijmegen; Medical Centre Haaglan- den, The Hague; Sint Maartens Hospital, Nijmegen. All Centres are located in the Netherlands. In all centres ethi- changes in arms and/or legs. Furthermore, the clinical sit- cal approval is obtained. uation is evaluated by the modified Japanese Orthopaedic Statistical analysis Association functional score[10] translated into the Dutch language. The validation of the Dutch translation is cur- The primary endpoint is clinical outcome after 1 year rently subject of investigation. Finally, a change in the using the modified Japanese Orthopaedic Association quality of life is evaluated by the Dutch Short Form – 36 functional score. Secondary outcomes are cost-effective- Health Survey. ness, quality of life measured by the SF-36, and complica- tions. Statistical analysis is performed by a blinded Follow – up will be at six weeks, six months, and after one investigator. For Statistical analysis the SAS system is used. year postoperatively (Table 2). Complications are noted Descriptive statistics are used to describe baseline charac- for their nature, duration and severity teristics. For comparison between groups student-t tests or chi – square tests are used. Statistical significance is Surgical technique reached when p < 0.05. Risk ratios (RR) and 95 % confi- Cervical laminectomy of the compressed levels is per- dence limits (CI) are presented. All analyses are done formed. Previous to the laminectomy a dorsal fusion is according to the intention – to – treat principle done. Dorsal fusion includes lateral mass screws from C2 to C6. In C2, C7 and the upper thoracic spine levels, pedi- The minimal clinically important difference was esti- cle screws will be placed. The screws are connected by rods mated by asking 4 international active spine surgeons or plates. Transverse connectors are used when indicated. what they would consider a clinically significant differ- In order to keep the posterior tension band intact, the ence in mJOA score. The mean of the values is considered fusion will extend from one level above the planned most the MCID. Table 2: overview of investigations at each clinical contact Preoperative Postoperative (po) 6 weeks po 3 months po 1 year po MRI X Plain cervical radiograph XX X X X mJOA XX X X SF-36 XX X X Neurologic examination by independent neurologist XX X Page 3 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 The sample size is calculated as follows: a difference of at I. Motor dysfunction score of the upper extremities least two points on the modified JOA functional score is Inability to move hands 0 considered significant. The difference is expected to be Inability to eat with a spoon but able to move hands 1 mainly allocated to the function of the arms and legs. Inability to button shirt but able to eat with a spoon 2 Based on literature, a standard deviation of approximately Able to button shirt with great difficulty 3 2 is assumed [12]. A two group student t test with a 0.05 Able to button shirt with slight difficulty 4 two sided significance level and a power of 95 % will need a sample size per group of 27 to detect a significant differ- No dysfunction 5 ence. Considering a ten percent of lost to follow up, a total of 30 individuals per group will be included. II. Motor dysfunction score of the lower extremities Complete loss of motor and sensory function 0 Randomisation Sensory preservation without ability to move legs 1 For randomisation, the closed envelope method is used. Able to move legs but unable to walk 2 As soon as informed consent is obtained, one of the treat- Able to walk on flat floor with a walking aid (i.e., cane or crutch) 3 ment options is assigned to the patient. The secretary of Able to walk up and/or down stairs with hand rail 4 the neurosurgical department in the Canisius Wilhelmina Hospital, Nijmegen, the Netherlands will control the ran- Moderate to significant lack of stability but able to 5 domisation. Prior to surgery, the patient is informed walk up and/or down stairs without hand rail about the chosen option. Patients who do not choose for Mild lack of stability but walk unaided with smooth reciprocation 6 participation, are offered one of the surgical options that No dysfunction 7 are currently under investigation. However, they are not followed in an observational cohort study. III. Sensation Complete loss of hand sensation 0 Endpoints Severe sensory loss or pain 1 Primary endpoints Mild sensory loss 2 Several score systems exist for grading the severity of cer- vical myelopathy. The modified Japanese Orthopedic No sensory loss 3 functional score (Fig. 2) evaluates four groups: the func- tion of the arms, of the legs, the micturation, and the sen- IV. Sphincter dysfunction score sibility of the hands. It has the major advantage that it Inability to micturate voluntarily 0 assesses these functions separately [10]. Although it has Marked difficulty with micturition 1 been established that outcome after decompressive sur- Mild to moderate difficulty with micturition 2 gery reaches a plateau at six months postoperatively [13], Normal micturition 3 the primary endpoint will be evaluated at one year post- operatively just to make sure. Mo Figure 2 dified Japanese Orthopaedic Association functional score Modified Japanese Orthopaedic Association functional score. Secondary endpoints Since instrumentation is added in the fusion group, the costs will be higher. On the other hand, it is assumed that a mean better recovery will take place in the fusion group. Status Questionnaire is a widely-used generic health sta- Therefore, the additional costs (nursing costs, auxillary tus. This instrument consists of eight subscales and two supports, etc.) may be lower. A careful evaluation of the summary scales. On each scale higher scores indicate bet- costs of the treatment related to the outcome is per- ter outcomes. Scores can be compared with published age formed. To obtain a reliable insight in the costs the fol- – and sex – matched general population or disease-spe- lowing will be noted in a kind of diary: hospitalisation, cific norms [14]. Furthermore, it has been validated for out – patient contacts, additional medication, house cervical spondylotic myelopathy [15]. keeping support, instruments to support daily activities, e.g. walking, eating etcetera. Of each item the sort and Complications are separately registered. Complications amount will be recorded. related to the cervical myelopathy are postoperative hem- orrhage, postoperative infection, temporary or permanent Apart from the cost – effectiveness, the difference in the impairment of neurologic function, and kyphotic defor- general health status will be evaluated. It is assumed that mation of the cervical spine[7]. Complications related to general health will improve more after of a laminectomy adding lateral mass screws or/and pedicle screws are ver- with a fusion than one without. This will be reflected in a tebral artery injury and temporary or permanent nerve difference of the SF – 36 score. The Short Form 36 Health root damage[7]. In order to prevent damage to the spinal Page 4 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 cord, the instrumentation should be completed before the Through the age restriction, the results of the study cannot laminectomy. be generalized to the whole population. However, most often the patients with a symptomatic, degenerative, cer- Monitored events vical spinal canal stenosis will be 60 years old or older Monitored events are the death of a patient, withdrawal [16]. from the study, lost to follow – up, and cross – over from their randomly assigned treatment group. These events are Since knowledge of the instrumentation and of biome- registered within the case record form. The circumstances chanics of the cervical spine is necessary to avoid compli- of the events are investigated and also noted. In case of cations and to optimise instrumented fusion only death of the patient, a search for a relationship with the experienced spinal surgeons will collaborate with this instituted treatment is started. Throughout the study, all study. This will prevent a discussion related to the pre- medical complications and intervening treatments con- sumed different skill levels of the surgeons in case of an cerning the cervical spine are registered within the CRF at unexpected result. the usual follow – up visits or when the appropriate infor- mation reaches the treating surgeon. Finally, as a measure for the definitive clinical result the mJOA is chosen. This is the only scale that takes the ambu- Protocol violations latory function, the function of the hands, the sensibility Any of the following will be considered as a deviation of the hands, and the micturation pattern separately into from the protocol: randomization of an ineligible patient, account. This scale is validated for the Japanese popula- enrollment of a patient that is already participating in an tion [17]. However, its English translation has never been another study, enrollment of an participant to this study validated. Now, the English mJOA has been translated in another study, a patient receiving the wrong treatment, into Dutch. The validation of this translation is currently loss of radiology or any other data, and informed consent under investigation. violations. Violations are reviewed monthly and reported to the independent study supervisor (R.D. Donk, M.D., Finally, Lamifuse tries to measure a difference in costs. Canisius Wilhelmina Hospital, Nijmegen). Since most of the patient will not be working anymore but are retired, costs of material or personal support, extra Subject confidentiality medication etcetera will be calculated. These costs are spe- The anonymity of the subjects will be maintained. Sub- cific for the Netherlands, and cannot be extrapolated to jects will be identified by their initials and a subject other countries. number assigned by the secretary of the neurosurgical department in the Canisius Wilhelmina Hospital, Conclusion Nijmegen, the Netherlands. All CRFs and other docu- Laminectomy for symptomatic cervical spinal stenisos is ments submitted to the investigator will be assigned this frequently performed. However, not only compressive code. The secretary will enter the data of the patient and forces are responsible for the complaints of the patient. their assigned code. This list is only accessible for the prin- Continuing motion of the spinal cord over anterior cipal investigator, and the independent supervisor. spondylophytic ridges is also believed to be a causative factor. Fusion will prevent motion. This randomised, con- Discussion trolled study will compare the clinical results of laminec- Movement as an cause additional to stenosis of cervical tomy without and with fusion for patients with a myelopathy has been recognised for longer time. A posi- symptomatic stenosis of the cervical spinal canal. The tive effect of fusion in addition to decompression by lam- design of Lamifuse is discussed as are its limitations. inectomy has been reported earlier. To our knowledge, the is the first randomised controlled trial comparing lami- Competing interests nectomy without and with dorsal instrumented fusion. The author(s) declare that they have no competing inter- Apart from the clinical effectiveness, a study is needed to ests. explore the costeffectiveness of the treatments. Authors' contributions Several problems may arise. Randomization may be R.B. Generating the idea, writing the manuscript, epide- refused by some patients. However, experience from ear- miological background lier trials learned that after correct description of the pos- sibilities and estimated outcomes patients will not be A.V. epidemiological background, revising manuscript reluctant to be enrolled. J.A. revising manuscript Page 5 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 Acknowledgements The authors want to express their gratitude to the following neurosur- geons and orthopedic surgeons W.C. Peul, The Hague, The Netherlands; J. Harms and R. Melcher, Karlsbad Langensteinbach, Germany; B, Guiot, Tampa, FL, USA; M. Fehlings, Toronto, Canada for their collaboration in estimating the minimal clinically important difference in mJOA score. References 1. Shedid D, Benzel EC: Cervical spondylosis anatomy: pathophys- iology and biomechanics. Neurosurgery 2007, 60 S:S1-7-S1-13. 2. Henderson FC, Geddes JF, Vacarro AR, Woodard E, Berry KJ: Stretch - associated injury in cervical spondylotic myelopa- thy: new concept and review. Neurosurgery 2005, 56:1101-1113. 3. Fehlings MG, Skaf G: A review of the pathophysiology of cervi- cal spondylotic myelopathy with insights for potential novel mechanisms drawn from traumatic spinal cord injury. Spine 1998, 23:2730-2736. 4. Baptiste DC, Fehlings MG: Pathophysiology of cervical myelop- athy. Spine J 2006, 6:190S-197S. 5. Baron EM, Young WF: Cervical spondylotic myelopathy: a brief review of its pathophysiology, clinicical course, and diagno- sis. Neurosurgery 2007, 60S:S35-S41. 6. Mazanec D, Reddy A: Medical management of cervical spondy- losis. Neurosurgery 2007, 60S:S43-S59. 7. Wiggins GC, Shaffrey CI: Dorsal surgery for myelopathy and myeloradiculopathy. Neurosurgery 2007, 60S:S71-S81. 8. LaRocca H: Cervical spondylotic myelopathy: natural history. Spine 1988, 13:854-855. 9. Houten JK, Cooper PR: Laminectomy and posterior cervical plating for multilevel cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament: effects on cervical alignment, spinal cord compression, and neurologi- cal outcome. Neurosurgery 2003, 52:1081-1087. 10. Benzel EC, Lancon J, Kesterson L, Hadden T: Cervical laminec- tomy and dentate ligament section for cervical spondylotic myelopathy. J Spinal Disord 1991, 4:286-295. 11. Lapsiwala S, Benzel E: Surgical management of cevical myelop- athy dealing with the cervical-thoracic junction. Spine J 2006, 6 (suppl):268S-273S. 12. de Rota FJJ, Meschian S, de Rota FA, Urbano V, Baron M: Cervical spondylotic myelopathy due to chronic compression: the role of signal intensity changes in magnetic resonance images. J Neurosurg 2007, Spine 6:17-22. 13. Cheung WY, Arvinte D, Wong YW, Luk KD, Cheung KM: Neuro- logical recovery after surgical decompression in patients with cervical spondylotic myelopathy - a prospective study. Int Orthop 2007, Jan 19:. 14. Ware J, Sherbourne D: The MOS 36 - item short-form health survey. Med Care 1992, 30:473-483. 15. Jankowitz BT, Gerszten PC: Decompression for cervical mye- lopathy. Spine J 2006, 6:317S-322S. 16. Matz PG, Pritchard PR, Hadley MN: Anterior cervical approach for the treatment of cervical myelopathy. Neurosurgery 2007, 60:s64-s70. 17. Yonenobu K, Abumi K, Nagata K, Taketomi E, Ueyama K: Interob- server and intraobserver reliability of the Japanese Ortho- paedic Association Scoring system for evaluation of cervical compression myelopathy. Spine 2001, 26:1890-1895. Publish with Bio Med Central and every scientist can read your work free of charge Pre-publication history The pre-publication history for this paper can be accessed "BioMed Central will be the most significant development for here: disseminating the results of biomedical researc h in our lifetime." Sir Paul Nurse, Cancer Research UK http://www.biomedcentral.com/1471-2474/8/111/pre Your research papers will be: pub available free of charge to the entire biomedical community peer reviewed and published immediately upon acceptance cited in PubMed and archived on PubMed Central yours — you keep the copyright BioMedcentral Submit your manuscript here: http://www.biomedcentral.com/info/publishing_adv.asp Page 6 of 6 (page number not for citation purposes) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png BMC Musculoskeletal Disorders Springer Journals

Design of Lamifuse: a randomised, multi-centre controlled trial comparing laminectomy without or with dorsal fusion for cervical myeloradiculopathy

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Springer Journals
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Medicine & Public Health; Orthopedics; Rehabilitation; Rheumatology; Sports Medicine; Internal Medicine; Epidemiology
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Abstract

Background: laminectomy is a valuable surgical treatment for some patients with a cervical radiculomyelopathy due to cervical spinal stenosis. More recently attention has been given to motion of the spinal cord over spondylotic spurs as a cause of myelopathic changes. Immobilisation by fusion could have a positive effect on the recovery of myelopathic signs or changes. This has never been investigated in a prospective, randomised trial. Lamifuse is an acronyme for laminectomy and fusion. Methods/Design: Lamifuse is a multicentre, randomised controlled trial comparing laminectomy with and without fusion in patients with a symptomatic cervical canal stenosis. The study population will be enrolled from patients that are 60 years or older with myelopathic signs and/or symptoms due to a cervical canal stenosis. A kyphotis shape of the cervical spine is an exclusion criterium. Each treatment arm needs 30 patients. Discussion: This study will contribute to the discussion whether additional fusion after a cervical laminectomy results in a better clinical outcome. ISRCT number: ISRCTN72800446 sometimes instability occurs. This may lead to a stenosis Background Cervical spondylosis is a progressive degenerative disease of the cervical spinal canal. In most instances it will of the spine. As people grow older, the prevalence of cer- remain asymptomatic. However, in some persons the ste- vical spondylosis increases. It is a natural process of aging. nosis of the spinal canal leads to a compression of the spi- Cervical spondylosis is seen in 10% of individuals in the nal cord. It is important to realize that not only static age of 25 years, whereas in 95% of the persons of 65 years compression leads to neurological symptoms, but also [1]. dynamic factors do. In a normal situation the spinal cord will move during flexion and extension. Ventral osteo- Due to the degenerative process reduction of height of the phytes in the spinal canal prevent up – and downward intervertebral discs, formation of spondylophytes and movement [1]. Furthermore, the spinal cord is more Page 1 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 stretched over the anterior bars increasing axial tension Methods/Design within the spinal cord. These forces are multidirectional Hypothesis Patients that are surgically treated for signs and symptoms creating secondary shearing forces resulting in stretch and shear injury to myelin and neural elements [2-4]. due to a stenosis of the cervical spinal canal have a better clinical outcome when a dorsal fusion is performed in Patients may present with a diversity of well known signs addition to a laminectomy compared to those that have and symptoms with variable intensities. Disturbance of solely a laminectomy. the sensibility in the arms, clumsiness of the hands and problems with micturation may occur. However, the hall- At the end of the study, the quality of life, complications, mark symptoms are gait abnormalities, weakness of the and the costs will be evaluated comparing these two treat- legs or stiffness of the legs [1,5]. ment groups. The natural course of the cervical myelopathy is variable. In – and exclusion criteria But patients developing mild or moderate symptoms are Patients with a minimal age of 60 years are included less likely to improve spontaneously. Non operative treat- (Table 1). At neurologic examination myelopathic ment will mainly affect neck pain or accompanying radic- changes must be apparent. At magnetic resonance imag- ulopathy. Improvement has been noted but is variable ing, concordant stenotic alterations at the cervical level(s) [6,7]. Patients with myelopathic signs and symptoms will, must be present. At the plain sitting lateral radiograph a however, likely benefit from surgery [5,7,8]. lordotic spine must be shown. The shape of the cervical spine is lordotic when the vertebral bodies of C3 to C6 are Surgical approaches for cervical myelopathy due to cervi- in front of a line drawn from a point of the posterior infe- cal spondylosis can be anterior, posterior or combined. rior part of the vertebral body of C2 to a point at the pos- The last option is reserved for deformity correction. In terior superior part of the vertebral body of C7 (Figure 1). most instances a lordotic or slight kyphotic cervical spine is present. The choice for an anterior or posterior Only patients that sign the informed consent after some approach is dependent on the main site of compression, time of reflection (1 week) are included. the shape of the cervical sagittal curvature and to a lesser account on the preference of the surgeon. Clinical evaluation and follow up At the first intake, duration of symptoms, other diseases, Dorsal approaches are laminectomy or laminoplasty. A severity of signs and symptoms are noted. Neurologic difference in clinical outcome has never been established. examination is performed by an independent neurologist. Prevention of post – laminectomy kyphosis is a reason for At follow up, the severity of signs and symptoms are also laminoplasty. If an additional, instrumented dorsal noted. Special attention is given to the myelopathic fusion is performed, the change of developing a post-sur- gical kyphosis is nearly zero[9]. It should be memorized that spondylotic processes also generate reduced motion of the spinal segments, a natural course [1]. From this point of view, decompression with fusion will have better clinical results when compared to decompression solely. In literature, indications in this direction are found. Fre- quently used dorsal fusion techniques today use lateral mass screws and cervical pedicle screws. This is relatively safe with a minimal persistent complication rate. Further- more, in experienced hands these techniques do not add substantial time to the duration of the surgery [7,9]. Despite a long-lasting interest in the various techniques, the clinical superiority of one method over the other has never been established. To our knowledge, a randomized controlled trial comparing laminectomy with or without Li C2 to the posterior superior p C7 in kyphotic cervical curve (B) Figure 1 ne fr case of om the p a normal cervical osterior inferioralordotic curv rt o f part of the vertebral body of the verteb ature (A ral body of ) and a fusion has never been performed. Line from the posterior inferior part of the vertebral body of C2 to the posterior superior part o f the vertebral body of C7 in case of a normal cervical lordotic curvature (A) and a kyphotic cervical curve (B). Page 2 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 Table 1: in – and exclusioncriteria cranial laminectomy level to at least one level below the most caudal planned laminectomy site. If the lowest level Inclusion Exclusion of fusion would include C7 or lower extension of the fusion to the upper thoracic spine (Th2 or Th3) is recom- 60 years or older Previous cervical surgery for mended[11]. This extension of the fusion is thought to myelopathic signs and symptoms Cervical myelopathic Solely radiculopathy, or most prevent junction disease at the cervicothoracic junction. symptoms and or signs at important complaint For example, if the laminectomy includes the levels C4 to neurologic examination C6, the fusion would be from C3 to C7. Because C7 is the Stenosis of cervical spinal canal Unable to undergo MRI lowest fusion level, incorporation of Th1 is recom- at MRI mended. Lordotic shape at lateral Life expectancy less than 2 years cervical plain radiograph, or at lateral cervical radiograph in Surgical demands extension Since fusion is added, only centres with a known spinal Informed consent Other diseases interfering with surgical experience are asked to participate. The surgeons neurologic symptoms and signs, for example spinal cord glioma, thoracic performing a laminectomy should also be experienced in herniated disc with spinal cord lateral mass fixation techniques, especially lateral mass compression, multiple sclerosis etc. and cervical pedicle screws. Rheumatoid arthritis Trauma to the neck in history Study Sites Diseases interfering with rehabilitation, for example severe The following centres will paricipate: Radboud University cardiac congestive disease. Nijmegen Medical Centre, Nijmegen; Canisius Wil- Participation in another study helmina Hospital, Nijmegen; Medical Centre Haaglan- den, The Hague; Sint Maartens Hospital, Nijmegen. All Centres are located in the Netherlands. In all centres ethi- changes in arms and/or legs. Furthermore, the clinical sit- cal approval is obtained. uation is evaluated by the modified Japanese Orthopaedic Statistical analysis Association functional score[10] translated into the Dutch language. The validation of the Dutch translation is cur- The primary endpoint is clinical outcome after 1 year rently subject of investigation. Finally, a change in the using the modified Japanese Orthopaedic Association quality of life is evaluated by the Dutch Short Form – 36 functional score. Secondary outcomes are cost-effective- Health Survey. ness, quality of life measured by the SF-36, and complica- tions. Statistical analysis is performed by a blinded Follow – up will be at six weeks, six months, and after one investigator. For Statistical analysis the SAS system is used. year postoperatively (Table 2). Complications are noted Descriptive statistics are used to describe baseline charac- for their nature, duration and severity teristics. For comparison between groups student-t tests or chi – square tests are used. Statistical significance is Surgical technique reached when p < 0.05. Risk ratios (RR) and 95 % confi- Cervical laminectomy of the compressed levels is per- dence limits (CI) are presented. All analyses are done formed. Previous to the laminectomy a dorsal fusion is according to the intention – to – treat principle done. Dorsal fusion includes lateral mass screws from C2 to C6. In C2, C7 and the upper thoracic spine levels, pedi- The minimal clinically important difference was esti- cle screws will be placed. The screws are connected by rods mated by asking 4 international active spine surgeons or plates. Transverse connectors are used when indicated. what they would consider a clinically significant differ- In order to keep the posterior tension band intact, the ence in mJOA score. The mean of the values is considered fusion will extend from one level above the planned most the MCID. Table 2: overview of investigations at each clinical contact Preoperative Postoperative (po) 6 weeks po 3 months po 1 year po MRI X Plain cervical radiograph XX X X X mJOA XX X X SF-36 XX X X Neurologic examination by independent neurologist XX X Page 3 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 The sample size is calculated as follows: a difference of at I. Motor dysfunction score of the upper extremities least two points on the modified JOA functional score is Inability to move hands 0 considered significant. The difference is expected to be Inability to eat with a spoon but able to move hands 1 mainly allocated to the function of the arms and legs. Inability to button shirt but able to eat with a spoon 2 Based on literature, a standard deviation of approximately Able to button shirt with great difficulty 3 2 is assumed [12]. A two group student t test with a 0.05 Able to button shirt with slight difficulty 4 two sided significance level and a power of 95 % will need a sample size per group of 27 to detect a significant differ- No dysfunction 5 ence. Considering a ten percent of lost to follow up, a total of 30 individuals per group will be included. II. Motor dysfunction score of the lower extremities Complete loss of motor and sensory function 0 Randomisation Sensory preservation without ability to move legs 1 For randomisation, the closed envelope method is used. Able to move legs but unable to walk 2 As soon as informed consent is obtained, one of the treat- Able to walk on flat floor with a walking aid (i.e., cane or crutch) 3 ment options is assigned to the patient. The secretary of Able to walk up and/or down stairs with hand rail 4 the neurosurgical department in the Canisius Wilhelmina Hospital, Nijmegen, the Netherlands will control the ran- Moderate to significant lack of stability but able to 5 domisation. Prior to surgery, the patient is informed walk up and/or down stairs without hand rail about the chosen option. Patients who do not choose for Mild lack of stability but walk unaided with smooth reciprocation 6 participation, are offered one of the surgical options that No dysfunction 7 are currently under investigation. However, they are not followed in an observational cohort study. III. Sensation Complete loss of hand sensation 0 Endpoints Severe sensory loss or pain 1 Primary endpoints Mild sensory loss 2 Several score systems exist for grading the severity of cer- vical myelopathy. The modified Japanese Orthopedic No sensory loss 3 functional score (Fig. 2) evaluates four groups: the func- tion of the arms, of the legs, the micturation, and the sen- IV. Sphincter dysfunction score sibility of the hands. It has the major advantage that it Inability to micturate voluntarily 0 assesses these functions separately [10]. Although it has Marked difficulty with micturition 1 been established that outcome after decompressive sur- Mild to moderate difficulty with micturition 2 gery reaches a plateau at six months postoperatively [13], Normal micturition 3 the primary endpoint will be evaluated at one year post- operatively just to make sure. Mo Figure 2 dified Japanese Orthopaedic Association functional score Modified Japanese Orthopaedic Association functional score. Secondary endpoints Since instrumentation is added in the fusion group, the costs will be higher. On the other hand, it is assumed that a mean better recovery will take place in the fusion group. Status Questionnaire is a widely-used generic health sta- Therefore, the additional costs (nursing costs, auxillary tus. This instrument consists of eight subscales and two supports, etc.) may be lower. A careful evaluation of the summary scales. On each scale higher scores indicate bet- costs of the treatment related to the outcome is per- ter outcomes. Scores can be compared with published age formed. To obtain a reliable insight in the costs the fol- – and sex – matched general population or disease-spe- lowing will be noted in a kind of diary: hospitalisation, cific norms [14]. Furthermore, it has been validated for out – patient contacts, additional medication, house cervical spondylotic myelopathy [15]. keeping support, instruments to support daily activities, e.g. walking, eating etcetera. Of each item the sort and Complications are separately registered. Complications amount will be recorded. related to the cervical myelopathy are postoperative hem- orrhage, postoperative infection, temporary or permanent Apart from the cost – effectiveness, the difference in the impairment of neurologic function, and kyphotic defor- general health status will be evaluated. It is assumed that mation of the cervical spine[7]. Complications related to general health will improve more after of a laminectomy adding lateral mass screws or/and pedicle screws are ver- with a fusion than one without. This will be reflected in a tebral artery injury and temporary or permanent nerve difference of the SF – 36 score. The Short Form 36 Health root damage[7]. In order to prevent damage to the spinal Page 4 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 cord, the instrumentation should be completed before the Through the age restriction, the results of the study cannot laminectomy. be generalized to the whole population. However, most often the patients with a symptomatic, degenerative, cer- Monitored events vical spinal canal stenosis will be 60 years old or older Monitored events are the death of a patient, withdrawal [16]. from the study, lost to follow – up, and cross – over from their randomly assigned treatment group. These events are Since knowledge of the instrumentation and of biome- registered within the case record form. The circumstances chanics of the cervical spine is necessary to avoid compli- of the events are investigated and also noted. In case of cations and to optimise instrumented fusion only death of the patient, a search for a relationship with the experienced spinal surgeons will collaborate with this instituted treatment is started. Throughout the study, all study. This will prevent a discussion related to the pre- medical complications and intervening treatments con- sumed different skill levels of the surgeons in case of an cerning the cervical spine are registered within the CRF at unexpected result. the usual follow – up visits or when the appropriate infor- mation reaches the treating surgeon. Finally, as a measure for the definitive clinical result the mJOA is chosen. This is the only scale that takes the ambu- Protocol violations latory function, the function of the hands, the sensibility Any of the following will be considered as a deviation of the hands, and the micturation pattern separately into from the protocol: randomization of an ineligible patient, account. This scale is validated for the Japanese popula- enrollment of a patient that is already participating in an tion [17]. However, its English translation has never been another study, enrollment of an participant to this study validated. Now, the English mJOA has been translated in another study, a patient receiving the wrong treatment, into Dutch. The validation of this translation is currently loss of radiology or any other data, and informed consent under investigation. violations. Violations are reviewed monthly and reported to the independent study supervisor (R.D. Donk, M.D., Finally, Lamifuse tries to measure a difference in costs. Canisius Wilhelmina Hospital, Nijmegen). Since most of the patient will not be working anymore but are retired, costs of material or personal support, extra Subject confidentiality medication etcetera will be calculated. These costs are spe- The anonymity of the subjects will be maintained. Sub- cific for the Netherlands, and cannot be extrapolated to jects will be identified by their initials and a subject other countries. number assigned by the secretary of the neurosurgical department in the Canisius Wilhelmina Hospital, Conclusion Nijmegen, the Netherlands. All CRFs and other docu- Laminectomy for symptomatic cervical spinal stenisos is ments submitted to the investigator will be assigned this frequently performed. However, not only compressive code. The secretary will enter the data of the patient and forces are responsible for the complaints of the patient. their assigned code. This list is only accessible for the prin- Continuing motion of the spinal cord over anterior cipal investigator, and the independent supervisor. spondylophytic ridges is also believed to be a causative factor. Fusion will prevent motion. This randomised, con- Discussion trolled study will compare the clinical results of laminec- Movement as an cause additional to stenosis of cervical tomy without and with fusion for patients with a myelopathy has been recognised for longer time. A posi- symptomatic stenosis of the cervical spinal canal. The tive effect of fusion in addition to decompression by lam- design of Lamifuse is discussed as are its limitations. inectomy has been reported earlier. To our knowledge, the is the first randomised controlled trial comparing lami- Competing interests nectomy without and with dorsal instrumented fusion. The author(s) declare that they have no competing inter- Apart from the clinical effectiveness, a study is needed to ests. explore the costeffectiveness of the treatments. Authors' contributions Several problems may arise. Randomization may be R.B. Generating the idea, writing the manuscript, epide- refused by some patients. However, experience from ear- miological background lier trials learned that after correct description of the pos- sibilities and estimated outcomes patients will not be A.V. epidemiological background, revising manuscript reluctant to be enrolled. J.A. revising manuscript Page 5 of 6 (page number not for citation purposes) BMC Musculoskeletal Disorders 2007, 8:111 http://www.biomedcentral.com/1471-2474/8/111 Acknowledgements The authors want to express their gratitude to the following neurosur- geons and orthopedic surgeons W.C. Peul, The Hague, The Netherlands; J. Harms and R. Melcher, Karlsbad Langensteinbach, Germany; B, Guiot, Tampa, FL, USA; M. Fehlings, Toronto, Canada for their collaboration in estimating the minimal clinically important difference in mJOA score. References 1. Shedid D, Benzel EC: Cervical spondylosis anatomy: pathophys- iology and biomechanics. Neurosurgery 2007, 60 S:S1-7-S1-13. 2. Henderson FC, Geddes JF, Vacarro AR, Woodard E, Berry KJ: Stretch - associated injury in cervical spondylotic myelopa- thy: new concept and review. Neurosurgery 2005, 56:1101-1113. 3. Fehlings MG, Skaf G: A review of the pathophysiology of cervi- cal spondylotic myelopathy with insights for potential novel mechanisms drawn from traumatic spinal cord injury. Spine 1998, 23:2730-2736. 4. Baptiste DC, Fehlings MG: Pathophysiology of cervical myelop- athy. Spine J 2006, 6:190S-197S. 5. Baron EM, Young WF: Cervical spondylotic myelopathy: a brief review of its pathophysiology, clinicical course, and diagno- sis. Neurosurgery 2007, 60S:S35-S41. 6. Mazanec D, Reddy A: Medical management of cervical spondy- losis. Neurosurgery 2007, 60S:S43-S59. 7. Wiggins GC, Shaffrey CI: Dorsal surgery for myelopathy and myeloradiculopathy. Neurosurgery 2007, 60S:S71-S81. 8. LaRocca H: Cervical spondylotic myelopathy: natural history. Spine 1988, 13:854-855. 9. Houten JK, Cooper PR: Laminectomy and posterior cervical plating for multilevel cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament: effects on cervical alignment, spinal cord compression, and neurologi- cal outcome. Neurosurgery 2003, 52:1081-1087. 10. Benzel EC, Lancon J, Kesterson L, Hadden T: Cervical laminec- tomy and dentate ligament section for cervical spondylotic myelopathy. J Spinal Disord 1991, 4:286-295. 11. Lapsiwala S, Benzel E: Surgical management of cevical myelop- athy dealing with the cervical-thoracic junction. Spine J 2006, 6 (suppl):268S-273S. 12. de Rota FJJ, Meschian S, de Rota FA, Urbano V, Baron M: Cervical spondylotic myelopathy due to chronic compression: the role of signal intensity changes in magnetic resonance images. J Neurosurg 2007, Spine 6:17-22. 13. Cheung WY, Arvinte D, Wong YW, Luk KD, Cheung KM: Neuro- logical recovery after surgical decompression in patients with cervical spondylotic myelopathy - a prospective study. Int Orthop 2007, Jan 19:. 14. Ware J, Sherbourne D: The MOS 36 - item short-form health survey. Med Care 1992, 30:473-483. 15. Jankowitz BT, Gerszten PC: Decompression for cervical mye- lopathy. Spine J 2006, 6:317S-322S. 16. Matz PG, Pritchard PR, Hadley MN: Anterior cervical approach for the treatment of cervical myelopathy. Neurosurgery 2007, 60:s64-s70. 17. Yonenobu K, Abumi K, Nagata K, Taketomi E, Ueyama K: Interob- server and intraobserver reliability of the Japanese Ortho- paedic Association Scoring system for evaluation of cervical compression myelopathy. Spine 2001, 26:1890-1895. Publish with Bio Med Central and every scientist can read your work free of charge Pre-publication history The pre-publication history for this paper can be accessed "BioMed Central will be the most significant development for here: disseminating the results of biomedical researc h in our lifetime." Sir Paul Nurse, Cancer Research UK http://www.biomedcentral.com/1471-2474/8/111/pre Your research papers will be: pub available free of charge to the entire biomedical community peer reviewed and published immediately upon acceptance cited in PubMed and archived on PubMed Central yours — you keep the copyright BioMedcentral Submit your manuscript here: http://www.biomedcentral.com/info/publishing_adv.asp Page 6 of 6 (page number not for citation purposes)

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BMC Musculoskeletal Disorders – Springer Journals

Published: Nov 9, 2007

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