Technical Note
Cervical Microendoscopic Interlaminar Decompression through a Midline Approach in Patients with Cervical Myelopathy: A Technical Note Yasushi Oshima1,2 Katsushi Takeshita1 Hirohiko Inanami2 Tomoyuki Iwahori2 Satoshi Baba1 Sakae Tanaka1 1 Department of Orthopaedic Surgery, The University of Tokyo,
Tokyo, Japan 2 Department of Orthopaedic Surgery, Iwai Orthopaedic Medical Hospital, Tokyo, Japan
Yuichi Takano2
Hisashi Koga2
Address for correspondence Yasushi Oshima, MD, PhD, Department of Orthopaedic Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033, Japan (e-mail: [email protected]).
J Neurol Surg A 2014;75:474–478.
Abstract
Keywords
► cervical myelopathy ► microendoscopic decompression ► midline approach
received August 19, 2013 accepted January 16, 2014 published online May 12, 2014
Introduction Microendoscopic techniques through a unilateral paramedian approach or muscle-preserving techniques using a microscope have been reported as minimally invasive spinal decompression procedures for the cervical spine. In this study, we developed a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy. Methods A total of 29 consecutive patients with single- or two-level cervical compression myelopathy were reviewed. For the single-level cases (e.g., C5–C6), a midline skin incision, 2 cm in length, was made at the spinal level to be decompressed (C5–C6) under fluoroscopic guidance. The nuchal ligament was longitudinally cut, and tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. A dome-like laminectomy of C5, partial laminectomy of the upper part of C6, and flavectomy were performed. For the two-level cases (e.g., C4–C5 and C5–C6), the decompression procedure was completed by splitting the spinous process (C5). Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score. Neck and arm pain was also evaluated using a numerical rating scale (NRS). Results Overall, 10 patients underwent single-level decompression, and 19 patients underwent two-level decompression. The average age was 67 years (range: 40–83 years), and the mean follow-up period was 11 months (range: 4–14 months). The average pre- and postoperative JOA scores were 10.2 and 13.5, with a mean recovery rate of 49%. The mean preoperative and postoperative NRS scores were 3.5 and 1.5 for neck pain and 4.6 and 2.9 for arm pain, respectively. One patient showed transient mild weakness of the leg that recovered neurologically within a few weeks. No other postoperative complications were observed. Conclusion This procedure revealed good short-term surgical results. This technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an
© 2014 Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0034-1373663. ISSN 2193-6315.
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
474
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
475
Introduction Posterior decompression is one of the most common surgical interventions for cervical compression myelopathy. Although laminoplasty is an established procedure and good long-term results have been reported,1,2 postoperative axial neck pain is observed in some patients.3 A postoperative decrease in lordosis and range of motion has also been reported. Several minimally invasive spinal procedures for the cervical spine have been reported to solve these problems. Shiraishi et al developed a muscle-preserving technique by splitting the spinous process through an intermuscular midline approach using a microscope and reported good surgical results with minimal postoperative neck pain.4–6 Another potential minimally invasive procedure uses a microendoscope. Microendoscopic decompression surgery of the spine originated from lumbar microendoscopic discectomy, which utilizes an intramuscular paramedian approach. Yabuki et al developed this system for cervical myelopathy and introduced ipsilateral decompression through a paramedian approach using two bilateral skin incisions.7 Minamide et al reported a bilateral decompression technique using a unilateral paramedian approach for cervical myelopathy that was developed for lumbar spinal canal stenosis.8 One possible problem with the paramedian approach is the use of the intramuscular plane, which can lead to intra- or postoperative bleeding due to muscle damage compared with the intermuscular approach with the spinous process split via the midline. In addition, although retraction of the dura matter is occasionally required during lumbar surgery to decompress the contralateral side using a unilateral paramedian approach, this maneuver would be considerably dangerous when operating on the cervical spine and could lead to incomplete decompression of the opposite side. To overcome these problems, we report on a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy.
as by complete obstruction of the subarachnoid space and spinal cord compression on preoperative T2-weighted magnetic resonance images. Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score, and neck pain and arm pain were evaluated using a numerical rating scale (NRS).
Single-Level Surgical Technique A 2-cm midline skin incision was made under fluoroscopic guidance at the spinal level to be decompressed (C5–C6) (►Fig. 1). The nuchal ligament was longitudinally cut, and
Methods Twenty-nine consecutive patients who underwent singlelevel or two-level cervical compression myelopathy by a single surgeon (Y.O.) from June 2012 through April 2013 were reviewed. The diagnoses were cervical spondylotic myelopathy in 21 patients, ossification of the longitudinal ligament in 5 patients, and calcification of the ligamentum flavum in 3 patients. The level(s) at which compression occurred was identified by neurologic examinations as well
Fig. 1 (A) Preoperative computed tomography (CT) scans and T2-weighted magnetic resonance images (MRI) of a 56-year-old man who has a single-level spinal cord compression at C5–C6 26 years after an anterior cervical discectomy and fusion at C6–C7. (B) Postoperative CT scan and MRI showing domelike laminectomy of C5 and C6. Journal of Neurological Surgery—Part A
Vol. 75
No. A6/2014
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intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the unilateral approach. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
the tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. The set of the METRx endoscopic system (Medtronic Sofamor Danek, Memphis, Tennessee, United States) was used for the microendoscopic procedure. The tips of the spinous processes were occasionally drilled to make the retractor stable. Spinous processes were partially cut to make a working space for the decompression procedure when the interspinous space was narrow. The interspinalis muscles were spread bluntly. Deep attachment of the semispinalis cervicis and multifidus muscles was partly coagulated and dissected. Subsequently, a domelike laminectomy of C5 and partial laminectomy of the upper part of C6, together with a flavectomy, were performed that completed the single-level decompression. After decompression, the working channel was carefully removed and a drain was placed. The nuchal ligament and skin were closed using standard techniques.
Two-Level Surgical Technique A 2-cm midline skin incision was made at the spinal level to be decompressed (C6) under fluoroscopic guidance (►Fig. 2). An 18-mm tubular retractor was inserted after longitudinally cutting the nuchal ligament and exposing the tip of the spinous process (C6). The spinous process (C6) was split using a highspeed drill and divided at its base. A tubular retractor was subsequently inserted more deeply into the base of the targeted lamina (C6), and the lamina was thinned and removed. A domelike laminectomy of C5 and partial laminectomy of upper C7 was also performed, and the yellow ligaments of C5–C6 and C6–C7 were removed, thus completing the two-level decompression (C5–C6 and C6–C7). (►Fig. 3)
Statistical Analysis SPSS v.18 software (IBM, Inc., Armonk, New York, United States) was used for all statistical analysis, and a p value < 0.05 was considered significant. A nonparametric analysis was performed using a Wilcoxon signed rank test.
Results Of the 29 patients, 10 underwent single-level decompression and 19 underwent two-level decompression. The average age of the patients was 67 years (range: 40–83 years), and the mean follow-up period was 11 months (range: 4–14 months). The mean estimated intraoperative blood loss was 15 mL (range: 0–100 mL), and mean operative time was 112 minutes (range: 86–158 minutes). The average preand postoperative JOA scores were 10.2 and 13.5, respectively (p < 0.01), with a mean recovery rate of 49%. The average pre- and postoperative NRS score was 3.5 and 1.5 for neck pain (p < 0.01), and 4.6 and 2.9 for arm pain (p < 0.01) (►Table 1). All patients started walking the day after surgery without wearing a cervical brace. One patient showed transient mild weakness of the leg, which recovered neurologically within a few weeks. No other postoperative complications were observed. Journal of Neurological Surgery—Part A
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No. A6/2014
Fig. 2 (A) Preoperative computed tomography scans and magnetic resonance images of a 63-year-old man who has a spinal cord compression at C5–C6 and C6–C7. (B) Postoperative status. A C6 laminectomy was performed.
Discussion Microendoscopic decompression surgery has been primarily developed for herniated discs or spinal canal stenosis of the lumbar spine.9–12 Several reports have documented good surgical results from microendoscopic foraminotomy for cervical spondylotic radiculopathy.13–15 Only three reports are available on cervical spondylotic myelopathy; all used a paramedian approach off the midline.7,8,16 Those techniques are decompression procedures originally developed for lumbar disc herniation (paramedian approach and ipsilateral decompression) or lumbar spinal canal stenosis (paramedian approach and bilateral decompression). Although the surgical results reported in those studies are comparable with those of the conventional method,8,16 an asymmetric view of the surgical field through a paramedian approach is technically demanding and can lead to disorientation in the surgical field. Whereas the paramedian approach of the former microendoscopic techniques involves the intramuscular plane, our method utilizes the intermuscular plane through a midline
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
476
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
477
Table 1 Patient characteristics Age, y
67
Sex, male-to-female ratio
19:10
Blood loss, mL
15
JOA score Pre
10.2
Post
13.5
Improvement rate
49%
Pre
3.5
Post
1.5
Arm pain Pre
4.6
Post
2.9
Decompression levels Single level
10
Two levels
19
Operation time, min
Fig. 3 (A) Intraoperative microendoscopic view of the spinal cord after decompression. (B) Intraoperative lateral fluoroscopic view of the cervical spine showing placement of the tubular retractor and a highspeed burr. (C) Postoperative clinical photograph of the surgical wound (2 cm).
approach. We believe that this technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the paramedian approach. Shiraishi et al first reported the spinous process splitting procedure for selective cervical decompression as a minimally invasive procedure for cervical myelopathy through a midline approach.4 This technique uses microscopic visualization to minimize muscle damage and reduce postoperative axial pain. Our two-level decompression technique is a modification of Shiraishi’s method using a microendoscope. Yabuki et al reported several cases at a meeting in which the microendoscopic spinous process splitting procedure was performed, but the results have not been published online as far as we know.17 Our method using a microendoscope minimizes the skin incision to 2 cm and also minimizes muscle dissection and bony resection of the spinous process compared with those of Shiraishi’s technique with a microscope. In particular, we succeeded in completing the decompression procedure during single-level decompression cases without the need for splitting the spinous process. However, a
Single level
101
Two levels
119
single-handed technique is required with the use of a microendoscope, which has a steep learning curve. Multilevel laminectomies are associated with an increased risk for postlaminectomy kyphosis because of the potential destabilizing effects after removing the spinous process and supraspinous and interspinous structures.18,19 In contrast, the minimally invasive pinpoint procedures listed previously show potential for postoperative maintenance of cervical curvature. Because the posterior structure is maintained in our technique without significant damage to the paravertebral muscles in the same way, we speculate that the risk of postoperative kyphotic deformity is fairly low. Neck pain decreased significantly after surgery, and no patient showed severe axial pain. Recently, we have been applying this method to patients with three-level spinal cord compression, and the surgical results are as good as those for the single- and two-level cases. The contraindications of this technique are the same as those of the techniques described earlier. That is, patients with kyphosis, instability, or massive ossification of the posterior longitudinal ligament are not indicated for our procedure. Such patients require laminoplasty, laminectomy with fusion, or anterior fusion surgery. The limitation of this study was the lack of long-term follow-up. Nevertheless, although further studies are necessary, we speculate that the midterm surgical results will be satisfactory because this technique is not a new concept but a modification of established methods. Short-term results of CMID were satisfactory. This minimally invasive technique can be a good option for treating cervical compression myelopathy. Journal of Neurological Surgery—Part A
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No. A6/2014
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Neck pain
Cervical Microendoscopic Interlaminar Decompression
Conclusion
Oshima et al. 8 Minamide A, Yoshida M, Yamada H, et al. Clinical outcomes of
Short-term results of our novel technique, CMID through a midline approach, were satisfactory. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.
9 10
11
References
12
1 Seichi A, Takeshita K, Ohishi I, et al. Long-term results of double-
2
3
4
5 6
7
door laminoplasty for cervical stenotic myelopathy. Spine 2001; 26(5):479–487 Chiba K, Ogawa Y, Ishii K, et al. Long-term results of expansive open-door laminoplasty for cervical myelopathy—average 14-year follow-up study. Spine 2006;31(26):2998–3005 Hosono N, Yonenobu K, Ono K. Neck and shoulder pain after laminoplasty. A noticeable complication. Spine 1996;21(17): 1969–1973 Shiraishi T, Kato M, Yato Y, et al. New techniques for exposure of posterior cervical spine through intermuscular planes and their surgical application. Spine (Phila Pa 1976) 2012;37:E286–E296 Shiraishi T. A new technique for exposure of the cervical spine laminae. Technical note. J Neurosurg 2002;96(1 (Suppl):122–126 Shiraishi T. Skip laminectomy—a new treatment for cervical spondylotic myelopathy, preserving bilateral muscular attachments to the spinous processes: a preliminary report. Spine J 2002;2(2):108–115 Yabuki S, Kikuchi S. Endoscopic partial laminectomy for cervical myelopathy. J Neurosurg Spine 2005;2(2):170–174
13
14
15 16
17 18 19
microendoscopic decompression surgery for cervical myelopathy. Eur Spine J 2010;19(3):487–493 Foley KT, Smith MM, Rampersaud YR. Microendoscopic approach to far-lateral lumbar disc herniation. Neurosurg Focus 1999;7(5):e5 Perez-Cruet MJ, Foley KT, Isaacs RE, et al. Microendoscopic lumbar discectomy: technical note. Neurosurgery 2002;51(5 (Suppl): S129–S136 Khoo LT, Fessler RG. Microendoscopic decompressive laminotomy for the treatment of lumbar stenosis. Neurosurgery 2002;51 (5, Suppl):S146–S154 Ikuta K, Arima J, Tanaka T, et al. Short-term results of microendoscopic posterior decompression for lumbar spinal stenosis. Technical note. J Neurosurg Spine 2005;2(5):624–633 Fessler RG, Khoo LT. Minimally invasive cervical microendoscopic foraminotomy: an initial clinical experience. Neurosurgery 2002; 51(5, Suppl):S37–S45 Adamson TE. Microendoscopic posterior cervical laminoforaminotomy for unilateral radiculopathy: results of a new technique in 100 cases. J Neurosurg 2001;95(1, Suppl):51–57 Coric D, Adamson T. Minimally invasive cervical microendoscopic laminoforaminotomy. Neurosurg Focus 2008;25(2):E2 Dahdaleh NS, Wong AP, Smith ZA, Wong RH, Lam SK, Fessler RG. Microendoscopic decompression for cervical spondylotic myelopathy. Neurosurg Focus 2013;35(1):E8 Yabuki S, Konno S, Otani K, et al. Endoscopic surgery for degenerative cervical spine diseases. J Spine Res 2010;1:501 Wiggins GC, Shaffrey CI. Dorsal surgery for myelopathy and myeloradiculopathy. Neurosurgery 2007;60(1, Suppl 1):S71–S81 McAllister BD, Rebholz BJ, Wang JC. Is posterior fusion necessary with laminectomy in the cervical spine? Surg Neurol Int 2012;3 (Suppl 3):S225–S231
Commentary Johannes Schröder1 1 ZW-O Zentrum für Wirbelsäulenchirurgie, Am Finkenhügel 3,
Osnabrück, Germany (e-mail: [email protected])
The authors describe their technique of dorsal decompression for cervical myelopathy with the help of an endoscope attached to a tubular retractor. The technique is derived from lumbar decompression techniques. The authors report their technique of midline placement between the cervical spinal processes und interlaminar decompression in cases with mono- or bisegmental cervical myelopathy. “Posterior decompression is one of the most common surgical interventions for cervical compression myelopathy”. This is rather not true for the Central European patient mostly suffering from disc related anterior pathology. The treatment of cervical myelopathies follows two principles: either removal of the compressing structure (disc material or
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osteophytes originating from the disc) or in cases with multilevel compression multilevel laminectomies accompanied by instrumentation for kyphosis prevention allowing the myelon to shift dorsally and to shorten to some amount. Both principles are not achievable by the proposed technique. The technique shown is reserved for compression originating from dorsal by facet related pathology. The authors show excellent examples for their technique. I do not expect a major shift from anterior to posterior in the future. Nevertheless the authors show a technique, if carefully applied, is a valuable addition to our present approaches to cervical myelopathy.
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478
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Cervical Microendoscopic Interlaminar Decompression through a Midline Approach in Patients with Cervical Myelopathy: A Technical Note Yasushi Oshima1,2 Katsushi Takeshita1 Hirohiko Inanami2 Tomoyuki Iwahori2 Satoshi Baba1 Sakae Tanaka1 1 Department of Orthopaedic Surgery, The University of Tokyo,
Tokyo, Japan 2 Department of Orthopaedic Surgery, Iwai Orthopaedic Medical Hospital, Tokyo, Japan
Yuichi Takano2
Hisashi Koga2
Address for correspondence Yasushi Oshima, MD, PhD, Department of Orthopaedic Surgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033, Japan (e-mail: [email protected]).
J Neurol Surg A 2014;75:474–478.
Abstract
Keywords
► cervical myelopathy ► microendoscopic decompression ► midline approach
received August 19, 2013 accepted January 16, 2014 published online May 12, 2014
Introduction Microendoscopic techniques through a unilateral paramedian approach or muscle-preserving techniques using a microscope have been reported as minimally invasive spinal decompression procedures for the cervical spine. In this study, we developed a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy. Methods A total of 29 consecutive patients with single- or two-level cervical compression myelopathy were reviewed. For the single-level cases (e.g., C5–C6), a midline skin incision, 2 cm in length, was made at the spinal level to be decompressed (C5–C6) under fluoroscopic guidance. The nuchal ligament was longitudinally cut, and tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. A dome-like laminectomy of C5, partial laminectomy of the upper part of C6, and flavectomy were performed. For the two-level cases (e.g., C4–C5 and C5–C6), the decompression procedure was completed by splitting the spinous process (C5). Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score. Neck and arm pain was also evaluated using a numerical rating scale (NRS). Results Overall, 10 patients underwent single-level decompression, and 19 patients underwent two-level decompression. The average age was 67 years (range: 40–83 years), and the mean follow-up period was 11 months (range: 4–14 months). The average pre- and postoperative JOA scores were 10.2 and 13.5, with a mean recovery rate of 49%. The mean preoperative and postoperative NRS scores were 3.5 and 1.5 for neck pain and 4.6 and 2.9 for arm pain, respectively. One patient showed transient mild weakness of the leg that recovered neurologically within a few weeks. No other postoperative complications were observed. Conclusion This procedure revealed good short-term surgical results. This technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an
© 2014 Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0034-1373663. ISSN 2193-6315.
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
474
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
475
Introduction Posterior decompression is one of the most common surgical interventions for cervical compression myelopathy. Although laminoplasty is an established procedure and good long-term results have been reported,1,2 postoperative axial neck pain is observed in some patients.3 A postoperative decrease in lordosis and range of motion has also been reported. Several minimally invasive spinal procedures for the cervical spine have been reported to solve these problems. Shiraishi et al developed a muscle-preserving technique by splitting the spinous process through an intermuscular midline approach using a microscope and reported good surgical results with minimal postoperative neck pain.4–6 Another potential minimally invasive procedure uses a microendoscope. Microendoscopic decompression surgery of the spine originated from lumbar microendoscopic discectomy, which utilizes an intramuscular paramedian approach. Yabuki et al developed this system for cervical myelopathy and introduced ipsilateral decompression through a paramedian approach using two bilateral skin incisions.7 Minamide et al reported a bilateral decompression technique using a unilateral paramedian approach for cervical myelopathy that was developed for lumbar spinal canal stenosis.8 One possible problem with the paramedian approach is the use of the intramuscular plane, which can lead to intra- or postoperative bleeding due to muscle damage compared with the intermuscular approach with the spinous process split via the midline. In addition, although retraction of the dura matter is occasionally required during lumbar surgery to decompress the contralateral side using a unilateral paramedian approach, this maneuver would be considerably dangerous when operating on the cervical spine and could lead to incomplete decompression of the opposite side. To overcome these problems, we report on a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy.
as by complete obstruction of the subarachnoid space and spinal cord compression on preoperative T2-weighted magnetic resonance images. Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score, and neck pain and arm pain were evaluated using a numerical rating scale (NRS).
Single-Level Surgical Technique A 2-cm midline skin incision was made under fluoroscopic guidance at the spinal level to be decompressed (C5–C6) (►Fig. 1). The nuchal ligament was longitudinally cut, and
Methods Twenty-nine consecutive patients who underwent singlelevel or two-level cervical compression myelopathy by a single surgeon (Y.O.) from June 2012 through April 2013 were reviewed. The diagnoses were cervical spondylotic myelopathy in 21 patients, ossification of the longitudinal ligament in 5 patients, and calcification of the ligamentum flavum in 3 patients. The level(s) at which compression occurred was identified by neurologic examinations as well
Fig. 1 (A) Preoperative computed tomography (CT) scans and T2-weighted magnetic resonance images (MRI) of a 56-year-old man who has a single-level spinal cord compression at C5–C6 26 years after an anterior cervical discectomy and fusion at C6–C7. (B) Postoperative CT scan and MRI showing domelike laminectomy of C5 and C6. Journal of Neurological Surgery—Part A
Vol. 75
No. A6/2014
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the unilateral approach. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
the tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. The set of the METRx endoscopic system (Medtronic Sofamor Danek, Memphis, Tennessee, United States) was used for the microendoscopic procedure. The tips of the spinous processes were occasionally drilled to make the retractor stable. Spinous processes were partially cut to make a working space for the decompression procedure when the interspinous space was narrow. The interspinalis muscles were spread bluntly. Deep attachment of the semispinalis cervicis and multifidus muscles was partly coagulated and dissected. Subsequently, a domelike laminectomy of C5 and partial laminectomy of the upper part of C6, together with a flavectomy, were performed that completed the single-level decompression. After decompression, the working channel was carefully removed and a drain was placed. The nuchal ligament and skin were closed using standard techniques.
Two-Level Surgical Technique A 2-cm midline skin incision was made at the spinal level to be decompressed (C6) under fluoroscopic guidance (►Fig. 2). An 18-mm tubular retractor was inserted after longitudinally cutting the nuchal ligament and exposing the tip of the spinous process (C6). The spinous process (C6) was split using a highspeed drill and divided at its base. A tubular retractor was subsequently inserted more deeply into the base of the targeted lamina (C6), and the lamina was thinned and removed. A domelike laminectomy of C5 and partial laminectomy of upper C7 was also performed, and the yellow ligaments of C5–C6 and C6–C7 were removed, thus completing the two-level decompression (C5–C6 and C6–C7). (►Fig. 3)
Statistical Analysis SPSS v.18 software (IBM, Inc., Armonk, New York, United States) was used for all statistical analysis, and a p value < 0.05 was considered significant. A nonparametric analysis was performed using a Wilcoxon signed rank test.
Results Of the 29 patients, 10 underwent single-level decompression and 19 underwent two-level decompression. The average age of the patients was 67 years (range: 40–83 years), and the mean follow-up period was 11 months (range: 4–14 months). The mean estimated intraoperative blood loss was 15 mL (range: 0–100 mL), and mean operative time was 112 minutes (range: 86–158 minutes). The average preand postoperative JOA scores were 10.2 and 13.5, respectively (p < 0.01), with a mean recovery rate of 49%. The average pre- and postoperative NRS score was 3.5 and 1.5 for neck pain (p < 0.01), and 4.6 and 2.9 for arm pain (p < 0.01) (►Table 1). All patients started walking the day after surgery without wearing a cervical brace. One patient showed transient mild weakness of the leg, which recovered neurologically within a few weeks. No other postoperative complications were observed. Journal of Neurological Surgery—Part A
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No. A6/2014
Fig. 2 (A) Preoperative computed tomography scans and magnetic resonance images of a 63-year-old man who has a spinal cord compression at C5–C6 and C6–C7. (B) Postoperative status. A C6 laminectomy was performed.
Discussion Microendoscopic decompression surgery has been primarily developed for herniated discs or spinal canal stenosis of the lumbar spine.9–12 Several reports have documented good surgical results from microendoscopic foraminotomy for cervical spondylotic radiculopathy.13–15 Only three reports are available on cervical spondylotic myelopathy; all used a paramedian approach off the midline.7,8,16 Those techniques are decompression procedures originally developed for lumbar disc herniation (paramedian approach and ipsilateral decompression) or lumbar spinal canal stenosis (paramedian approach and bilateral decompression). Although the surgical results reported in those studies are comparable with those of the conventional method,8,16 an asymmetric view of the surgical field through a paramedian approach is technically demanding and can lead to disorientation in the surgical field. Whereas the paramedian approach of the former microendoscopic techniques involves the intramuscular plane, our method utilizes the intermuscular plane through a midline
This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.
476
Cervical Microendoscopic Interlaminar Decompression
Oshima et al.
477
Table 1 Patient characteristics Age, y
67
Sex, male-to-female ratio
19:10
Blood loss, mL
15
JOA score Pre
10.2
Post
13.5
Improvement rate
49%
Pre
3.5
Post
1.5
Arm pain Pre
4.6
Post
2.9
Decompression levels Single level
10
Two levels
19
Operation time, min
Fig. 3 (A) Intraoperative microendoscopic view of the spinal cord after decompression. (B) Intraoperative lateral fluoroscopic view of the cervical spine showing placement of the tubular retractor and a highspeed burr. (C) Postoperative clinical photograph of the surgical wound (2 cm).
approach. We believe that this technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the paramedian approach. Shiraishi et al first reported the spinous process splitting procedure for selective cervical decompression as a minimally invasive procedure for cervical myelopathy through a midline approach.4 This technique uses microscopic visualization to minimize muscle damage and reduce postoperative axial pain. Our two-level decompression technique is a modification of Shiraishi’s method using a microendoscope. Yabuki et al reported several cases at a meeting in which the microendoscopic spinous process splitting procedure was performed, but the results have not been published online as far as we know.17 Our method using a microendoscope minimizes the skin incision to 2 cm and also minimizes muscle dissection and bony resection of the spinous process compared with those of Shiraishi’s technique with a microscope. In particular, we succeeded in completing the decompression procedure during single-level decompression cases without the need for splitting the spinous process. However, a
Single level
101
Two levels
119
single-handed technique is required with the use of a microendoscope, which has a steep learning curve. Multilevel laminectomies are associated with an increased risk for postlaminectomy kyphosis because of the potential destabilizing effects after removing the spinous process and supraspinous and interspinous structures.18,19 In contrast, the minimally invasive pinpoint procedures listed previously show potential for postoperative maintenance of cervical curvature. Because the posterior structure is maintained in our technique without significant damage to the paravertebral muscles in the same way, we speculate that the risk of postoperative kyphotic deformity is fairly low. Neck pain decreased significantly after surgery, and no patient showed severe axial pain. Recently, we have been applying this method to patients with three-level spinal cord compression, and the surgical results are as good as those for the single- and two-level cases. The contraindications of this technique are the same as those of the techniques described earlier. That is, patients with kyphosis, instability, or massive ossification of the posterior longitudinal ligament are not indicated for our procedure. Such patients require laminoplasty, laminectomy with fusion, or anterior fusion surgery. The limitation of this study was the lack of long-term follow-up. Nevertheless, although further studies are necessary, we speculate that the midterm surgical results will be satisfactory because this technique is not a new concept but a modification of established methods. Short-term results of CMID were satisfactory. This minimally invasive technique can be a good option for treating cervical compression myelopathy. Journal of Neurological Surgery—Part A
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Neck pain
Cervical Microendoscopic Interlaminar Decompression
Conclusion
Oshima et al. 8 Minamide A, Yoshida M, Yamada H, et al. Clinical outcomes of
Short-term results of our novel technique, CMID through a midline approach, were satisfactory. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.
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References
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1 Seichi A, Takeshita K, Ohishi I, et al. Long-term results of double-
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door laminoplasty for cervical stenotic myelopathy. Spine 2001; 26(5):479–487 Chiba K, Ogawa Y, Ishii K, et al. Long-term results of expansive open-door laminoplasty for cervical myelopathy—average 14-year follow-up study. Spine 2006;31(26):2998–3005 Hosono N, Yonenobu K, Ono K. Neck and shoulder pain after laminoplasty. A noticeable complication. Spine 1996;21(17): 1969–1973 Shiraishi T, Kato M, Yato Y, et al. New techniques for exposure of posterior cervical spine through intermuscular planes and their surgical application. Spine (Phila Pa 1976) 2012;37:E286–E296 Shiraishi T. A new technique for exposure of the cervical spine laminae. Technical note. J Neurosurg 2002;96(1 (Suppl):122–126 Shiraishi T. Skip laminectomy—a new treatment for cervical spondylotic myelopathy, preserving bilateral muscular attachments to the spinous processes: a preliminary report. Spine J 2002;2(2):108–115 Yabuki S, Kikuchi S. Endoscopic partial laminectomy for cervical myelopathy. J Neurosurg Spine 2005;2(2):170–174
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17 18 19
microendoscopic decompression surgery for cervical myelopathy. Eur Spine J 2010;19(3):487–493 Foley KT, Smith MM, Rampersaud YR. Microendoscopic approach to far-lateral lumbar disc herniation. Neurosurg Focus 1999;7(5):e5 Perez-Cruet MJ, Foley KT, Isaacs RE, et al. Microendoscopic lumbar discectomy: technical note. Neurosurgery 2002;51(5 (Suppl): S129–S136 Khoo LT, Fessler RG. Microendoscopic decompressive laminotomy for the treatment of lumbar stenosis. Neurosurgery 2002;51 (5, Suppl):S146–S154 Ikuta K, Arima J, Tanaka T, et al. Short-term results of microendoscopic posterior decompression for lumbar spinal stenosis. Technical note. J Neurosurg Spine 2005;2(5):624–633 Fessler RG, Khoo LT. Minimally invasive cervical microendoscopic foraminotomy: an initial clinical experience. Neurosurgery 2002; 51(5, Suppl):S37–S45 Adamson TE. Microendoscopic posterior cervical laminoforaminotomy for unilateral radiculopathy: results of a new technique in 100 cases. J Neurosurg 2001;95(1, Suppl):51–57 Coric D, Adamson T. Minimally invasive cervical microendoscopic laminoforaminotomy. Neurosurg Focus 2008;25(2):E2 Dahdaleh NS, Wong AP, Smith ZA, Wong RH, Lam SK, Fessler RG. Microendoscopic decompression for cervical spondylotic myelopathy. Neurosurg Focus 2013;35(1):E8 Yabuki S, Konno S, Otani K, et al. Endoscopic surgery for degenerative cervical spine diseases. J Spine Res 2010;1:501 Wiggins GC, Shaffrey CI. Dorsal surgery for myelopathy and myeloradiculopathy. Neurosurgery 2007;60(1, Suppl 1):S71–S81 McAllister BD, Rebholz BJ, Wang JC. Is posterior fusion necessary with laminectomy in the cervical spine? Surg Neurol Int 2012;3 (Suppl 3):S225–S231
Commentary Johannes Schröder1 1 ZW-O Zentrum für Wirbelsäulenchirurgie, Am Finkenhügel 3,
Osnabrück, Germany (e-mail: [email protected])
The authors describe their technique of dorsal decompression for cervical myelopathy with the help of an endoscope attached to a tubular retractor. The technique is derived from lumbar decompression techniques. The authors report their technique of midline placement between the cervical spinal processes und interlaminar decompression in cases with mono- or bisegmental cervical myelopathy. “Posterior decompression is one of the most common surgical interventions for cervical compression myelopathy”. This is rather not true for the Central European patient mostly suffering from disc related anterior pathology. The treatment of cervical myelopathies follows two principles: either removal of the compressing structure (disc material or
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osteophytes originating from the disc) or in cases with multilevel compression multilevel laminectomies accompanied by instrumentation for kyphosis prevention allowing the myelon to shift dorsally and to shorten to some amount. Both principles are not achievable by the proposed technique. The technique shown is reserved for compression originating from dorsal by facet related pathology. The authors show excellent examples for their technique. I do not expect a major shift from anterior to posterior in the future. Nevertheless the authors show a technique, if carefully applied, is a valuable addition to our present approaches to cervical myelopathy.
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