- Email: [email protected]
Surgical efficacy of minimally invasive thoracic discectomy
Journal of Clinical Neuroscience xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Review
Surgical efficacy of minimally invasive thoracic discectomy Ali M. Elhadi 1, Aqib H. Zehri 1, Hasan A. Zaidi, Kaith K. Almefty, Mark C. Preul, Nicholas Theodore, Curtis A. Dickman ⇑ Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, 350 West Thomas Road, Phoenix, AZ 85013, USA
a r t i c l e
i n f o
Article history: Received 8 May 2015 Accepted 17 May 2015 Available online xxxx Keywords: Discectomy Endoscopy Minimally invasive Thoracic disc Thoracoscopic
a b s t r a c t We aimed to determine the clinical indications and surgical outcomes for thoracoscopic discectomy. Thoracic disc disease is a rare degenerative process. Thoracoscopic approaches serve to minimize tissue injury during the approach, but critics argue that this comes at the cost of surgical efficacy. Current reports in the literature are limited to small institutional patient series. We systematically identified all English language articles on thoracoscopic discectomy with at least two patients, published from 1994 to 2013 on MEDLINE, Science Direct, and Google Scholar. We analyzed 12 articles that met the inclusion criteria, five prospective and seven retrospective studies comprising 545 surgical patients. The overall complication rate was 24% (n = 129), with reported complications ranging from intercostal neuralgia (6.1%), atelectasis (2.8%), and pleural effusion (2.6%), to more severe complications such as pneumonia (0.8%), pneumothorax (1.3%), and venous thrombosis (0.2%). The average reported postoperative follow-up was 20.5 months. Complete resolution of symptoms was reported in 79% of patients, improvement with residual symptoms in 10.2%, no change in 9.6%, and worsening in 1.2%. The minimally invasive endoscopic approaches to the thoracic spine among selected patients demonstrate excellent clinical efficacy and acceptable complication rates, comparable to the open approaches. Disc herniations confined to a single level, with small or no calcifications, are ideal for such an approach, whereas patients with calcified discs adherent to the dura would benefit from an open approach. Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction Thoracic herniated discs are estimated to occur in approximately 12–37% of the population [1]. Compression of the thoracic spinal cord and/or nerve roots, resulting in myelopathy or radiculopathy, is rare, occurring in an estimated 1 in 1 million people [2]. The large hollow potential cavity of the thorax provides a natural working corridor for endoscopes, and the recent trend toward minimally invasive techniques (MIT) has fostered the relatively new field of thoracoscopic discectomy. This approach has gained significant popularity over the past decade [3–8]. The primary goal of minimally invasive thoracoscopic discectomy is to execute the same decompression as a classical open procedure, while the secondary goal is to reduce the approach-related tissue trauma [9]. However, MIT of the thoracic spine have been met with some resistance by the neurosurgical community, because of the potential for devastating complications, owed largely to the steep learning curve for this procedure [10]. Due to the rarity of this pathology ⇑ Corresponding author. Tel.: +1 602 406 3593; fax: +1 602 406 4104. 1
E-mail address: [email protected] (C.A. Dickman). These authors have contributed equally to the manuscript.
and the proportionately few spinal surgeons who perform thoracic discectomies via a minimally invasive approach, the institutional and single-surgeon series do not accurately assess the safety and efficacy of this approach. A systematic analysis of thoracoscopic surgery has not been performed since a study reported in 1988 [11] that reported 0% morbidity and mortality, but included only seven patients. The cumulative experience with this MIT is now significantly greater, and a more accurate assessment regarding the efficacy and risks for thoracoscopic discectomy is now possible. The aim of our current study is to pool the available data from the neurosurgical literature to determine the clinical indications and surgical outcomes for thoracoscopic discectomy. 2. Methods An extensive literature search was performed using MEDLINE, Science Direct, and Google Scholar, with the keywords ‘‘thoracoscopy,’’ ‘‘thoracic endoscopy,’’ ‘‘thoracoscopic herniated disc,’’ ‘‘thoracoscopic discectomy,’’ and ‘‘thoracoscopic discectomies’’, to identify the relevant articles published between January 1994 and December 2013. Original, peer-reviewed, prospective, or retrospective scientific papers with at least two patients were included
http://dx.doi.org/10.1016/j.jocn.2015.05.013 0967-5868/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
2
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
in the study. The exclusion criteria were the following: clinical data as determined by two independent reviewers, non-surgical treatment, non-English language manuscripts and non-human subjects. If multiple publications by a single institution or author clearly reported the same cohort of patients, only the most recently published article with the largest sample size was included for the final analyses. Each article was independently reviewed by two investigators, and the following data were extracted: study design, total number of patients, basic demographic data, surgical indications and pathological findings, the number of spinal levels surgically treated, previous surgical intervention, fusion rates, complication rates, perioperative morbidity, patient satisfaction rates. The manuscripts were also reviewed to collect the incidence of the following complications: pleural effusion, pleuritis, atelectasis, pneumothorax, venous thrombosis, pneumonia, subcutaneous emphysema, intercostal neuralgia, cerebrospinal fluid (CSF) or chyle leaks, dural tear, cardiovascular events, reintubation, wrong-level surgery, residual disc, open surgical bailout, neurological impairment, and other miscellaneous events or death. 3. Results A total of 125 articles were identified from the online database searches (Fig. 1). After filtering the reports that contained only
human subjects, English language publications, and a publication date between January 1994 and December 2013, we identified a total of 99 articles for review. Of these, 83 articles were excluded for the following reasons: case reports, thoracic herniated disc treated by a minimally invasive procedure other than a discectomy, procedures with a posterior approach, older studies if a newer study was present from the same institution or authors, articles that did not contain adequate clinical data as determined by two investigators, articles in which only a technical description was reported without clinical cases or patient outcomes, and cadaveric and animal studies. A total of 12 unique articles were identified based on our inclusion and exclusion criteria: five prospective [1,12–15] and seven retrospective reviews [16–22] (Fig. 1). The total number of patients was 545 patients, 201 men (42%), 279 women (58%), with sex not reported for 65 patients. The mean age was 48.2 years (range: 19–84). A total of 553 surgical procedures were performed on 584 thoracic disc levels (Table 1). The presenting symptoms were reported for 488 patients in 11 articles, and we divided the presenting symptoms into five main categories: radiculopathy in 39.5% (n = 193), myelopathy in 19.4% (n = 95), mixed symptoms in 19.0% (n = 93), low back pain in 12.1% (n = 59), and miscellaneous symptoms in 10.0% (n = 49). The miscellaneous symptoms included one or more of the
Fig. 1. Study selection flow diagram.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
3
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx Table 1 Published endoscopic thoracoscopic discectomy studies from 1994–2013 Study
Design
Patients, n (males/females)
Age, mean years
Procedures, n
Discs, n
Anand et al., 2002 [12] Bartels et al., 2007 [16] Gille et al., 2006 [17] Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Mack et al., 1995 [13] Oskouian et al., 2005 [14] Quint et al., 2012 [15] Sasani et al., 2011 [20] Wait et al., 2012 [1] Watanabe et al., 2007 [21] Yanni et al., 2011 [22] Total
Prospective Retrospective Retrospective Retrospective Retrospective Prospective Prospective Prospective Retrospective Prospective Retrospective Retrospective
100 (55/45) 7 (2/5) 18 (6/12) 7 (4/3) 3 (3/0) 57 (N/A) 46 (21/25) 167 (64/103) 11 (4/7) 121 (42/79) 3 (N/A) 5 (N/A) 545 (201/279, 65 N/A)
43 54.8 50.7 52 38.3 42.1 53.5 46.8 42.5 46.6 49.7 58.8 48.2
101 7 21 7 3 57 46 167 11 125 3 5 553
117 8 10 8 3 57 56 167 11 139 3 5 584
N/A = not available.
Table 2 Presenting symptoms of thoracic herniated disc
*
Symptom
Patients*, n (%)
Radiculopathy Myelopathy Mixed Low back pain Miscellaneous
193 (39.5) 95 (19.4) 93 (19.0) 59 (12.1) 49 (10.0)
surgeon. Table 3 shows the variations in the anterolateral surgical approach. The side of approach was based on the laterality of the disc bulge. Three articles reported the side used for thoracoscopic approaches [12,13,15] for a total of 352 patients, with a right-sided approach used in 73% (n = 255), and a left-sided approach in 28% (n = 97), despite the suggestions in the literature to avoid the right side when performing lower thoracic spine procedures due to the bulge produced by the diaphragm and liver.
n = 489.
following: other pain symptoms (n = 45) [12,18,22], paresthesia (n = 3) [20], gait problems (n = 6) [16], and paralysis or weakness (n = 3; Table 2) [12,22]. Wait et al. [1] also reported bowel or bladder symptoms, with urinary incontinence in 15.7% (n = 19) and both bowel and bladder symptoms in 6.6% (n = 8) of their 121 patients. No patients with isolated bowel symptoms as an associated or presenting symptom were reported. Nine articles [1,12,14–16,18–20,22] reported the spinal levels that were operated, with a total number of 514 levels with herniated disc pathology. The most common levels of pathology were T6–7 (100; 19.5%), T7–8 (120; 23.3%), T8–9 (82; 16%), and T9–10 (64; 13.5%). 3.1. Surgical techniques All 12 articles reported the use of an anterolateral transthoracic approach, with some minor variations. As previously described [13,23], the approach used three or four portals in a triangular or diamond configuration, depending on the comfort level of the
3.2. Complications The overall complication rate was 24% from 545 patients. Table 4 shows the complication rates as reported by the authors. Intercostal neuralgia was the most common complication and was reported in seven articles [12–17,21] with a rate of 6.0% (n = 33), followed by atelectasis, reported in four articles [12–15] with a rate of 2.8% (n = 15). Pleural effusion was reported in six articles with a rate of 2.6% (n = 14; range: 1–33%) [1,12,14,15,17,21]. Reintubation was performed in 0.6% (n = 3) of patients [1], and surgery was performed at the incorrect level in 0.37% (n = 2) [1,14]. There was residual disc in 1.1% (n = 6) of patients [1,14,15]. Neurological impairment in the form of nerve root injury occurred in 1.3% (n = 7) [13–16]. The majority of authors recommended that patients be draped in a manner that enabled a switch to an open surgery if necessary. Six patients (1.1%) were ultimately converted to open surgery, one being due to considerable pleural adhesions from a previous costotransversectomy, four due to epidural bleeding and/or dural tear, and one due to hypoxemia from underlying chronic obstructive pulmonary
Table 3 Variations of anterolateral approaches for minimally invasive thoracic discectomy Study
Anand et al., 2002 [12] Bartels et al., 2007 [16] Gille et al., 2006 [17] Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Mack et al., 1995 [13] Oskouian et al., 2005 [14] Quint et al., 2012 [15] Sasani et al., 2011 [20] Wait et al., 2012 [1] Watanabe et al., 2007 [21] Yanni et al., 2011 [22]
Type of approach
VATS Endoscopic thoracoscopy Thoracoscopic microsurgical discectomy Minimally invasive retropleural approach (dilators) VATS VATS VATS Thoracoscopic microdiscectomy Endoscopic thoracoscopy Thoracoscopic discectomy Endoscopic thoracoscopy Thoracoscopic microdiscectomy with tubular retraction system
Side, n Right
Left
84 N/A N/A N/A N/A 44 N/A 127 N/A N/A N/A N/A
16 N/A N/A N/A N/A 41 N/A 40 N/A N/A N/A N/A
N/A = not available, VATS = video-assisted thoracoscopic surgery.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
4
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
Table 4 Reported complications of minimally invasive thoracic discectomy Study
Patients with complications n
N
%
Anand et al., 2002 [12]
24
100
24
Bartels et al., 2007 [16]
4
7
57
Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Gille et al., 2006 [17]
0
7
0
0 15
3 18
0 83
Mack et al., 1995 [13]
15
57
26
Oskouian et al., 2005 [14]
19
46
41
Quint et al., 2012 [15]
26
167
16
Sasani et al., 2011 [20] Wait et al., 2012 [1]
1 22
11 121
9 18
Watanabe et al., 2007 [21]
2
3
67
Yanni et al., 2011 [22]
2
5
40
Complication type, n (%)
Pleural effusion, 2 (2.0) Pneumonia, 2 (2.0) Atelectasis, 6 (6.0) Pneumothorax, 5 (5.0) Intercostal neuralgia, 6 (6.0) Miscellaneous, 3 (3.0) Intercostal neuralgia, 2 (28.6) CSF leak, 1 (14.3) Neurological impairment, 1 (14.3) None None Pleural effusion, 1 (5.6) Intercostal neuralgia, 3 (16.7) Dural tear, 7 (38.9) Miscellaneous, 4 (22.2) Atelectasis, 5 (8.8) Intercostal neuralgia, 6 (10.5) Neurological impairment, 1 (1.8) Miscellaneous, 3 (5.3) Pleural effusion, 2 (4.3) Pneumonia, 2 (4.3) Atelectasis, 3 (6.5) Intercostal neuralgia, 6 (13.0) Chyle leak, 1 (2.2) Residual disc, 1 (2.2) Neurological impairment, 2 (4.3) Miscellaneous, 2 (4.3) Pleural effusion, 2 (1.2) Pleuritis, 1 (0.6) Atelectasis, 1 (0.6) Pneumothorax, 2 (1.2) Intercostal neuralgia, 9 (5.4) CSF leak, 1 (0.6) Dural tear, 1 (0.6) Residual disc, 3 (1.8) Neurological impairment, 3 (1.8) Miscellaneous, 3 (1.8) Pleuritis, 1 (9.1) Pleural effusion, 6 (5.0) Dural tear, 2 (1.7) Cardiovascular, 1 (0.8) Reintubation, 3 (2.5) Residual disc, 2 (1.7) Miscellaneous, 8 (6.6) Pleural effusion, 1 (33.3) Intercostal neuralgia, 1 (33.3) Venous thrombosis, 1 (20.0) Subcutaneous emphysema, 1 (20.0)
CSF = cerebrospinal fluid.
disease (1.1%) [1,12,17]. There was no reported mortality attributed to this procedure. 3.3. Outcomes The average postoperative follow-up period was 20.5 months (range: 12–48). Resolution or improvement of the presenting symptoms was reported in 79% of the patients, 9.5% reported that their symptoms did not change, and 11% reported worsening of symptoms. Kim et al. [19] and Sasani et al. [20] reported a change in the visual analog scale for pain evaluation from 7.5 to 1.5 and from 8.7 to 1.9, respectively, at the end of the follow-up period. The American Spinal Injury Association score was reported to have
improved postoperatively in two articles [17,22]. Anand et al. [12] reported an average improvement in the Oswestry disability index (ODI) score of 60% for Grade 4 patients, 37% for Grade 3A, 28% for Grade 3B, and 24% for Grade 1. Sasani et al. [20] reported an improvement in their patients in the average ODI from 88.3% preoperatively to 24.5% by the end of a mean follow-up of 24 months (Table 5).
4. Discussion Nearly 94% of thoracic herniated discs are in the midline [24], necessitating an anterolateral approach to the pathology. These are performed through a thoracotomy, which allows for a wider surgical field with less manipulation of the spinal cord and a lower risk of neurological deterioration. However, anterior thoracotomy is associated with significant morbidity and may be difficult to justify, particularly for patients with only mild symptoms. The approach necessitates a large skin incision, lung collapse and retraction, and rib resection with the assistance of an approach surgeon. This can contribute to postoperative pulmonary dysfunction and pain, and prolonged hospital stays. Thoracotomy to treat thoracic herniated discs has an average complication rate of 11.5% [25]. Although advancements have been made in transthoracic approaches over the course of 60 years, recent data from Wait et al. suggest that the complication rate is still as high as 28%, with 15.4% of patients suffering from pulmonary complications [1]. The advent of thoracoscopic approaches for cardiothoracic disease has fostered the development of minimally invasive approaches for ventral thoracic spinal disease. Here, we report the largest systematic review to date of this relatively novel surgical approach. Our data suggest that thoracoscopic discectomy provides excellent clinical results with acceptable rates of morbidity and mortality when performed by an experienced surgeon in properly selected patients.
4.1. Advantages Our systematic review highlights the multiple advantages that thoracoscopy has over open thoracotomy. Open surgery can have a significant rate of intercostal neuralgia, ranging from 7.1% to as high as 50% [8,26]. MIT has an intercostal neuralgia rate of 6.2%, which is likely attributable to the smaller surgical incision and the lack of need for a rib resection or retraction. The thoracoscopic approach offers a reduction in pain due to decreased chest wall injury, as compared with open thoracotomy which is often associated with postthoracotomy syndrome. This syndrome may resolve over several years or, in some patients, become permanent [25]. The pulmonary complications in open transthoracic surgery ranged from 3.4–41% in the literature [1,8,25,26]. Our systematic review demonstrated a pulmonary complication rate of 7.9%, which includes complications such as pleural effusions, pneumonia, atelectasis, pneumothorax, and pleuritis. This rate is comparable with open surgery, since both procedures require single lung deflation on the ipsilateral side and single lung ventilation [27]. In our systematic review, there were 22 reoperations, six of which were performed with open surgery. Five of these reoperations were to remove residual discs, mostly from an intradural location which required additional vertebral body resection. The remaining reoperations were for a misidentified level, dural tears, and spinal instability. None of these procedures necessitated an open surgical bailout. The low frequency of reoperation demonstrates the effectiveness of the thoracoscopic approach in removing symptomatic thoracic herniated discs. These results suggest that,
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
5
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx Table 5 Outcome and follow-up of minimally invasive thoracic discectomy Study
Patients, n Presenting symptoms, n (%)
Follow-up
Follow-up, monthsa
Anand et al., 2002 [12]
100
Predominant axial pain, 28 (28) Thoracic radicular pain, 5 (5) Axial and thoracic radicular pain, 38 (38) Axial and lower leg pain with or without thoracic radicular pain, 19 (19) Myelopathy, 8 (8) Paretic-paralytic, 2 (2)
ODI: Average improvement by grade, Grade 4 (60%), Grade 3A (37%), Grade 3B (28%), Grade 1 (24%)
Bartels et al., 2007 [16]
7
Myelopathy with gait disturbances, 6 (86) Frankel Grade: Preop 1C and 6D, 6 weeks postop 4D and 3E, Mixed, 1 (14) last follow-up 3D and 4E
13
Gille et al., 2006 [17]
18
Myelopathy, 18 (100)
ASIA score improved in three patients, tone improved in all, mean VAS score 1.5
12
Kasliwal and Deutsch, 2011 [18] 7
Myelopathy, 3 (43) Mixed pain, 4 (57)
Nurick scale: three patients improved by 1 point
16
Kim et al., 2007 [19]
3
Radiculopathy, 1 (33) Myelopathy, 2 (67)
VAS score improved from 7.5 to 1.5
15
Mack et al., 1995 [13]
57
N/A
49 (86%) with total relief of symptoms, 23 (40%) with total relief of pain, 26 (46%) with moderate to marked relief of symptoms, 8 (14%) with no improvement
Oskouian et al., 2005 [14]
46
Radiculopathy, 21 (46) Myelopathy, 25 (54)
Improvement in myelopathy by a mean of two Frankel grades in 18 (40%), unchanged in 27 (59%), 1 worsened; improvement of radiculopathy with ODI from 60 to 14 in 75%
12
Quint et al., 2012 [15]b
167
Radiculopathy, 80 (52.3) Low back pain, 16 (10.4) Combined pain, 57 (37)
48 (31%) excellent, 73 (48%) good, 26 (17%) regular, 6 (4%) poor results
24
Sasani et al., 2011 [20]
11
Low back pain, 8 (73) Back pain with paresthesia, 3 (27)
VAS score: 8.7 (preop), 4.7 (3 month postop), 2.8 (6 month postop), 1.8 (12 month postop), 1.9 (24 month postop); ODI: 88.3 (preop), 40.1 (3 month postop), 37 (6 month postop), 26.3 (12 month postop), 24.5 (24 month postop)
24
Wait et al., 2012 [1]c
121
Radiculopathy, 46 (43) Myelopathy, 35 (28.9) Combined pain, 33 (27.2) Low back pain, 2 (2)
Radiculopathy:67 (83.8%) complete resolution, 11 (13.8%) improvement, 1 (1.2%) no change, 1 (1.2%) worsened; Myelopathy: 50 (73.5%) reduction, 18 (26.5%) no change, 1 (1.5%) worsened; Back pain: 21 (56.8%) complete resolution, 11 (29.7%) improvement, 5 (13.5%) no change in back pain
29
Yanni et al., 2011 [22]
5
Myelopathy, 1 (20) Left extremity weakness and gait difficulty/axial pain, 1 (20) Midthoracic pain, 1 (20) Proximal leg weakness, 1 (20) Axial pain with girdling pain, 1 (20)
Nurick scale: 1 point improvement in three patients; ASIA: 1 letter improvement in two patients
12
48
N/A
ASIA = American Spinal Injury Association, N/A = not available, ODI = Oswestry disability index, postop = postoperative, preop = preoperative, VAS = visual analog scale. a Last follow-up. b Presenting symptom information was not available for all patients in the study. c Patients may have had one or more symptoms with varying outcomes by symptom.
for the appropriately selected patient, thoracoscopy maintains the advantages of anterior surgery with comparable rates of pulmonary complications and reduced rates of intercostal neuralgia. Our review also indicates that minimally invasive thoracoscopic approaches to treat thoracic herniated discs have excellent clinical results. We found that only 1.2% of patients had worsened symptoms that were not resolved at last follow-up, 9.6% had no improvement in symptoms, 10.2% had improved but residual symptoms, and 79% had complete resolution of symptoms over an average follow-up of 20.5 months. 4.2. Disadvantages While our data support the use of thoracoscopy, proper patient selection is critical to avoid reoperation, conversion to open surgery, and surgical complications. Symptomatic patients may have thoracic discs that are large, calcified, transdural, and adherent to the dura. In one study that evaluated the clinical and surgical outcomes of patients with giant herniated discs (those occupying 40% of the diameter of the spinal cord), the authors determined that thoracotomy is better suited for the removal of calcified giant
thoracic herniated discs, while thoracoscopy is better suited for soft giant thoracic herniated discs. When discs were ossified, transdural, and massive, the authors reported a switch from thoracoscopy (n = 4) to open surgery to minimize any compression of the spinal cord during resection of the mass [1]. Overall, the literature indicates that thoracoscopy is better suited for soft thoracic discs. Although they were rare complications in our analyses, dural tears and CSF leaks did occur. The requirement of reoperations can be avoided by using an open approach to treat intradural ossified thoracic herniated discs. The open approach affords the surgeon more precise bimanual dexterity which is necessary for water-tight dural closure [28]. Additionally, there are reported contraindications to a minimally invasive procedure that may lower the complication rate further. Wait et al. included preexisting pleural disease, pleural symphysis, previous thoracotomy due to possible pleural adhesions, and inability to tolerate single lung ventilation as relative contraindications [1]. Additionally, thoracoscopy can be used from T1 to T12 to treat multiple pathologies, but our group previously found that levels T1–4 and T11–L1 may be more appropriately accessed via a non-endoscopic approach [1].
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
6
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
A final consideration in thoracoscopic discectomy is the relatively steep learning curve for surgeons. The specific endoscopic instrumentation, 2D endoscopic images, and operating through a small opening to reach the spine at a longer distance and greater angle, are unique to endoscopy and may not be intuitive to surgeons who are accustomed to open procedures [1,19]. Our institution previously reported an initial complication rate of 28.6% that declined to 5.3% in the first 9 years of experience [1]. This trend is also demonstrated by the reduction in overall complication rates in each study as the number of patients who underwent the procedure increased. This suggests that many of the complications reported in this series may be prevented with improved training and surgical experience, in addition to improved patient selection, as previously mentioned. 5. Conclusion Thoracoscopic spinal surgery is a safe and effective alternative for thoracic discectomy in a properly selected subset of patients, and in the hands of an experienced surgeon. Our results and personal experience indicate that thoracoscopic discectomy should be the preferred treatment in soft, centrally located thoracic discs between T4 and T11 because of the less invasive nature of the procedure and the reduced rate of intercostal neuralgia. Open thoracotomy is indicated for large calcified or intradural disc herniations and other thoracic levels. Overall, with appropriately selected patients and proper surgical training, thoracoscopy maintains the advantages of anterior surgery, with comparable rates of pulmonary complications, reduced rates of intercostal neuralgia, and, most importantly, improved patient outcomes as compared to open surgery. Future prospective trials with long term follow-up data are necessary to truly assess the clinical efficacy of this approach. Conflicts of Interest/Disclosures The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication. References [1] Wait SD, Fox Jr DJ, Kenny KJ, et al. Thoracoscopic resection of symptomatic herniated thoracic discs: clinical results in 121 patients. Spine (Phila Pa 1976) 2012;37:35–40. [2] Carson J, Gumpert J, Jefferson A. Diagnosis and treatment of thoracic intervertebral disc protrusions. J Neurol Neurosurg Psychiatry 1971;34:68–77. [3] Beisse R. Endoscopic surgery on the thoracolumbar junction of the spine. Eur Spine J 2006;15:687–704. [4] Burke TG, Caputy AJ. Treatment of thoracic disc herniation: evolution toward the minimally invasive thoracoscopic technique. Neurosurg Focus 2000;9:e9.
[5] Jho HD. Endoscopic transpedicular thoracic discectomy. Neurosurg Focus 2000;9:e4. [6] Lidar Z, Lifshutz J, Bhattacharjee S, et al. Minimally invasive, extracavitary approach for thoracic disc herniation: technical report and preliminary results. Spine J 2006;6:157–63. [7] Regev GJ, Salame K, Behrbalk E, et al. Minimally invasive transforaminal, thoracic microscopic discectomy: technical report and preliminary results and complications. Spine J 2012;12:570–6. [8] Rosenthal D. Endoscopic approaches to the thoracic spine. Eur Spine J 2000;9:S8–S16. [9] Landreneau RJ, Hazelrigg SR, Mack MJ, et al. Postoperative pain-related morbidity: video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56:1285–9. [10] Sheikh H, Samartzis D, Perez-Cruet MJ. Techniques for the operative management of thoracic disc herniation: minimally invasive thoracic microdiscectomy. Orthop Clin North Am 2007;38:351–61 [abstract vi]. [11] Bohlman HH, Zdeblick TA. Anterior excision of herniated thoracic discs. J Bone Joint Surg Am 1988;70:1038–47. [12] Anand N, Regan JJ. Video-assisted thoracoscopic surgery for thoracic disc disease: classification and outcome study of 100 consecutive cases with a 2year minimum follow-up period. Spine (Phila Pa 1976) 2002;27:871–9. [13] Mack MJ, Regan JJ, McAfee PC, et al. Video-assisted thoracic surgery for the anterior approach to the thoracic spine. Ann Thorac Surg 1995;59:1100–6. [14] Oskouian RJ, Johnson JP. Endoscopic thoracic microdiscectomy. J Neurosurg Spine 2005;3:459–64. [15] Quint U, Bordon G, Preissl I, et al. Thoracoscopic treatment for single level symptomatic thoracic disc herniation: a prospective followed cohort study in a group of 167 consecutive cases. Eur Spine J 2012;21:637–45. [16] Bartels RH, Peul WC. Mini-thoracotomy or thoracoscopic treatment for medially located thoracic herniated disc? Spine (Phila Pa 1976) 2007;32:E581–4. [17] Gille O, Soderlund C, Razafimahandri HJ, et al. Analysis of hard thoracic herniated discs: review of 18 cases operated by thoracoscopy. Eur Spine J 2006;15:537–42. [18] Kasliwal MK, Deutsch H. Minimally invasive retropleural approach for central thoracic disc herniation. Minim Invasive Neurosurg 2011;54:167–71. [19] Kim SJ, Sohn MJ, Ryoo JY, et al. Clinical analysis of video-assisted thoracoscopic spinal surgery in the thoracic or thoracolumbar spinal pathologies. J Korean Neurosurg Soc 2007;42:293–9. [20] Sasani M, Fahir Ozer A, Oktenoglu T, et al. Thoracoscopic surgery for thoracic disc herniation. J Neurosurg Sci 2011;55:391–5. [21] Watanabe K, Yabuki S, Konno S, et al. Complications of endoscopic spinal surgery: a retrospective study of thoracoscopy and retroperitoneoscopy. J Orthop Sci 2007;12:42–8. [22] Yanni DS, Connery C, Perin NI. Video-assisted thoracoscopic surgery combined with a tubular retractor system for minimally invasive thoracic discectomy. Neurosurgery 2011;68:138–43 [discussion 143]. [23] Hott JS, Feiz-Erfan I, Kenny K, et al. Surgical management of giant herniated thoracic discs: analysis of 20 cases. J Neurosurg Spine 2005;3:191–7. [24] Stillerman CB, Chen TC, Couldwell WT, et al. Experience in the surgical management of 82 symptomatic herniated thoracic discs and review of the literature. J Neurosurg 1998;88:623–33. [25] Fessler RG, Sturgill M. Review: complications of surgery for thoracic disc disease. Surg Neurol 1998;49:609–18. [26] McCormick WE, Will SF, Benzel EC. Surgery for thoracic disc disease. Complication avoidance: overview and management. Neurosurg Focus 2000;9:e13. [27] Lall RR, Smith ZA, Wong AP, et al. Minimally invasive thoracic corpectomy: surgical strategies for malignancy, trauma, and complex spinal pathologies. Minim Invasive Surg 2012;2012:213791. [28] Perez-Cruet MJ, Fessler RG, Perin NI. Review: complications of minimally invasive spinal surgery. Neurosurgery 2002;51:S26–36.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Review
Surgical efficacy of minimally invasive thoracic discectomy Ali M. Elhadi 1, Aqib H. Zehri 1, Hasan A. Zaidi, Kaith K. Almefty, Mark C. Preul, Nicholas Theodore, Curtis A. Dickman ⇑ Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, 350 West Thomas Road, Phoenix, AZ 85013, USA
a r t i c l e
i n f o
Article history: Received 8 May 2015 Accepted 17 May 2015 Available online xxxx Keywords: Discectomy Endoscopy Minimally invasive Thoracic disc Thoracoscopic
a b s t r a c t We aimed to determine the clinical indications and surgical outcomes for thoracoscopic discectomy. Thoracic disc disease is a rare degenerative process. Thoracoscopic approaches serve to minimize tissue injury during the approach, but critics argue that this comes at the cost of surgical efficacy. Current reports in the literature are limited to small institutional patient series. We systematically identified all English language articles on thoracoscopic discectomy with at least two patients, published from 1994 to 2013 on MEDLINE, Science Direct, and Google Scholar. We analyzed 12 articles that met the inclusion criteria, five prospective and seven retrospective studies comprising 545 surgical patients. The overall complication rate was 24% (n = 129), with reported complications ranging from intercostal neuralgia (6.1%), atelectasis (2.8%), and pleural effusion (2.6%), to more severe complications such as pneumonia (0.8%), pneumothorax (1.3%), and venous thrombosis (0.2%). The average reported postoperative follow-up was 20.5 months. Complete resolution of symptoms was reported in 79% of patients, improvement with residual symptoms in 10.2%, no change in 9.6%, and worsening in 1.2%. The minimally invasive endoscopic approaches to the thoracic spine among selected patients demonstrate excellent clinical efficacy and acceptable complication rates, comparable to the open approaches. Disc herniations confined to a single level, with small or no calcifications, are ideal for such an approach, whereas patients with calcified discs adherent to the dura would benefit from an open approach. Ó 2015 Elsevier Ltd. All rights reserved.
1. Introduction Thoracic herniated discs are estimated to occur in approximately 12–37% of the population [1]. Compression of the thoracic spinal cord and/or nerve roots, resulting in myelopathy or radiculopathy, is rare, occurring in an estimated 1 in 1 million people [2]. The large hollow potential cavity of the thorax provides a natural working corridor for endoscopes, and the recent trend toward minimally invasive techniques (MIT) has fostered the relatively new field of thoracoscopic discectomy. This approach has gained significant popularity over the past decade [3–8]. The primary goal of minimally invasive thoracoscopic discectomy is to execute the same decompression as a classical open procedure, while the secondary goal is to reduce the approach-related tissue trauma [9]. However, MIT of the thoracic spine have been met with some resistance by the neurosurgical community, because of the potential for devastating complications, owed largely to the steep learning curve for this procedure [10]. Due to the rarity of this pathology ⇑ Corresponding author. Tel.: +1 602 406 3593; fax: +1 602 406 4104. 1
E-mail address: [email protected] (C.A. Dickman). These authors have contributed equally to the manuscript.
and the proportionately few spinal surgeons who perform thoracic discectomies via a minimally invasive approach, the institutional and single-surgeon series do not accurately assess the safety and efficacy of this approach. A systematic analysis of thoracoscopic surgery has not been performed since a study reported in 1988 [11] that reported 0% morbidity and mortality, but included only seven patients. The cumulative experience with this MIT is now significantly greater, and a more accurate assessment regarding the efficacy and risks for thoracoscopic discectomy is now possible. The aim of our current study is to pool the available data from the neurosurgical literature to determine the clinical indications and surgical outcomes for thoracoscopic discectomy. 2. Methods An extensive literature search was performed using MEDLINE, Science Direct, and Google Scholar, with the keywords ‘‘thoracoscopy,’’ ‘‘thoracic endoscopy,’’ ‘‘thoracoscopic herniated disc,’’ ‘‘thoracoscopic discectomy,’’ and ‘‘thoracoscopic discectomies’’, to identify the relevant articles published between January 1994 and December 2013. Original, peer-reviewed, prospective, or retrospective scientific papers with at least two patients were included
http://dx.doi.org/10.1016/j.jocn.2015.05.013 0967-5868/Ó 2015 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
2
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
in the study. The exclusion criteria were the following: clinical data as determined by two independent reviewers, non-surgical treatment, non-English language manuscripts and non-human subjects. If multiple publications by a single institution or author clearly reported the same cohort of patients, only the most recently published article with the largest sample size was included for the final analyses. Each article was independently reviewed by two investigators, and the following data were extracted: study design, total number of patients, basic demographic data, surgical indications and pathological findings, the number of spinal levels surgically treated, previous surgical intervention, fusion rates, complication rates, perioperative morbidity, patient satisfaction rates. The manuscripts were also reviewed to collect the incidence of the following complications: pleural effusion, pleuritis, atelectasis, pneumothorax, venous thrombosis, pneumonia, subcutaneous emphysema, intercostal neuralgia, cerebrospinal fluid (CSF) or chyle leaks, dural tear, cardiovascular events, reintubation, wrong-level surgery, residual disc, open surgical bailout, neurological impairment, and other miscellaneous events or death. 3. Results A total of 125 articles were identified from the online database searches (Fig. 1). After filtering the reports that contained only
human subjects, English language publications, and a publication date between January 1994 and December 2013, we identified a total of 99 articles for review. Of these, 83 articles were excluded for the following reasons: case reports, thoracic herniated disc treated by a minimally invasive procedure other than a discectomy, procedures with a posterior approach, older studies if a newer study was present from the same institution or authors, articles that did not contain adequate clinical data as determined by two investigators, articles in which only a technical description was reported without clinical cases or patient outcomes, and cadaveric and animal studies. A total of 12 unique articles were identified based on our inclusion and exclusion criteria: five prospective [1,12–15] and seven retrospective reviews [16–22] (Fig. 1). The total number of patients was 545 patients, 201 men (42%), 279 women (58%), with sex not reported for 65 patients. The mean age was 48.2 years (range: 19–84). A total of 553 surgical procedures were performed on 584 thoracic disc levels (Table 1). The presenting symptoms were reported for 488 patients in 11 articles, and we divided the presenting symptoms into five main categories: radiculopathy in 39.5% (n = 193), myelopathy in 19.4% (n = 95), mixed symptoms in 19.0% (n = 93), low back pain in 12.1% (n = 59), and miscellaneous symptoms in 10.0% (n = 49). The miscellaneous symptoms included one or more of the
Fig. 1. Study selection flow diagram.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
3
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx Table 1 Published endoscopic thoracoscopic discectomy studies from 1994–2013 Study
Design
Patients, n (males/females)
Age, mean years
Procedures, n
Discs, n
Anand et al., 2002 [12] Bartels et al., 2007 [16] Gille et al., 2006 [17] Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Mack et al., 1995 [13] Oskouian et al., 2005 [14] Quint et al., 2012 [15] Sasani et al., 2011 [20] Wait et al., 2012 [1] Watanabe et al., 2007 [21] Yanni et al., 2011 [22] Total
Prospective Retrospective Retrospective Retrospective Retrospective Prospective Prospective Prospective Retrospective Prospective Retrospective Retrospective
100 (55/45) 7 (2/5) 18 (6/12) 7 (4/3) 3 (3/0) 57 (N/A) 46 (21/25) 167 (64/103) 11 (4/7) 121 (42/79) 3 (N/A) 5 (N/A) 545 (201/279, 65 N/A)
43 54.8 50.7 52 38.3 42.1 53.5 46.8 42.5 46.6 49.7 58.8 48.2
101 7 21 7 3 57 46 167 11 125 3 5 553
117 8 10 8 3 57 56 167 11 139 3 5 584
N/A = not available.
Table 2 Presenting symptoms of thoracic herniated disc
*
Symptom
Patients*, n (%)
Radiculopathy Myelopathy Mixed Low back pain Miscellaneous
193 (39.5) 95 (19.4) 93 (19.0) 59 (12.1) 49 (10.0)
surgeon. Table 3 shows the variations in the anterolateral surgical approach. The side of approach was based on the laterality of the disc bulge. Three articles reported the side used for thoracoscopic approaches [12,13,15] for a total of 352 patients, with a right-sided approach used in 73% (n = 255), and a left-sided approach in 28% (n = 97), despite the suggestions in the literature to avoid the right side when performing lower thoracic spine procedures due to the bulge produced by the diaphragm and liver.
n = 489.
following: other pain symptoms (n = 45) [12,18,22], paresthesia (n = 3) [20], gait problems (n = 6) [16], and paralysis or weakness (n = 3; Table 2) [12,22]. Wait et al. [1] also reported bowel or bladder symptoms, with urinary incontinence in 15.7% (n = 19) and both bowel and bladder symptoms in 6.6% (n = 8) of their 121 patients. No patients with isolated bowel symptoms as an associated or presenting symptom were reported. Nine articles [1,12,14–16,18–20,22] reported the spinal levels that were operated, with a total number of 514 levels with herniated disc pathology. The most common levels of pathology were T6–7 (100; 19.5%), T7–8 (120; 23.3%), T8–9 (82; 16%), and T9–10 (64; 13.5%). 3.1. Surgical techniques All 12 articles reported the use of an anterolateral transthoracic approach, with some minor variations. As previously described [13,23], the approach used three or four portals in a triangular or diamond configuration, depending on the comfort level of the
3.2. Complications The overall complication rate was 24% from 545 patients. Table 4 shows the complication rates as reported by the authors. Intercostal neuralgia was the most common complication and was reported in seven articles [12–17,21] with a rate of 6.0% (n = 33), followed by atelectasis, reported in four articles [12–15] with a rate of 2.8% (n = 15). Pleural effusion was reported in six articles with a rate of 2.6% (n = 14; range: 1–33%) [1,12,14,15,17,21]. Reintubation was performed in 0.6% (n = 3) of patients [1], and surgery was performed at the incorrect level in 0.37% (n = 2) [1,14]. There was residual disc in 1.1% (n = 6) of patients [1,14,15]. Neurological impairment in the form of nerve root injury occurred in 1.3% (n = 7) [13–16]. The majority of authors recommended that patients be draped in a manner that enabled a switch to an open surgery if necessary. Six patients (1.1%) were ultimately converted to open surgery, one being due to considerable pleural adhesions from a previous costotransversectomy, four due to epidural bleeding and/or dural tear, and one due to hypoxemia from underlying chronic obstructive pulmonary
Table 3 Variations of anterolateral approaches for minimally invasive thoracic discectomy Study
Anand et al., 2002 [12] Bartels et al., 2007 [16] Gille et al., 2006 [17] Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Mack et al., 1995 [13] Oskouian et al., 2005 [14] Quint et al., 2012 [15] Sasani et al., 2011 [20] Wait et al., 2012 [1] Watanabe et al., 2007 [21] Yanni et al., 2011 [22]
Type of approach
VATS Endoscopic thoracoscopy Thoracoscopic microsurgical discectomy Minimally invasive retropleural approach (dilators) VATS VATS VATS Thoracoscopic microdiscectomy Endoscopic thoracoscopy Thoracoscopic discectomy Endoscopic thoracoscopy Thoracoscopic microdiscectomy with tubular retraction system
Side, n Right
Left
84 N/A N/A N/A N/A 44 N/A 127 N/A N/A N/A N/A
16 N/A N/A N/A N/A 41 N/A 40 N/A N/A N/A N/A
N/A = not available, VATS = video-assisted thoracoscopic surgery.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
4
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
Table 4 Reported complications of minimally invasive thoracic discectomy Study
Patients with complications n
N
%
Anand et al., 2002 [12]
24
100
24
Bartels et al., 2007 [16]
4
7
57
Kasliwal and Deutsch, 2011 [18] Kim et al., 2007 [19] Gille et al., 2006 [17]
0
7
0
0 15
3 18
0 83
Mack et al., 1995 [13]
15
57
26
Oskouian et al., 2005 [14]
19
46
41
Quint et al., 2012 [15]
26
167
16
Sasani et al., 2011 [20] Wait et al., 2012 [1]
1 22
11 121
9 18
Watanabe et al., 2007 [21]
2
3
67
Yanni et al., 2011 [22]
2
5
40
Complication type, n (%)
Pleural effusion, 2 (2.0) Pneumonia, 2 (2.0) Atelectasis, 6 (6.0) Pneumothorax, 5 (5.0) Intercostal neuralgia, 6 (6.0) Miscellaneous, 3 (3.0) Intercostal neuralgia, 2 (28.6) CSF leak, 1 (14.3) Neurological impairment, 1 (14.3) None None Pleural effusion, 1 (5.6) Intercostal neuralgia, 3 (16.7) Dural tear, 7 (38.9) Miscellaneous, 4 (22.2) Atelectasis, 5 (8.8) Intercostal neuralgia, 6 (10.5) Neurological impairment, 1 (1.8) Miscellaneous, 3 (5.3) Pleural effusion, 2 (4.3) Pneumonia, 2 (4.3) Atelectasis, 3 (6.5) Intercostal neuralgia, 6 (13.0) Chyle leak, 1 (2.2) Residual disc, 1 (2.2) Neurological impairment, 2 (4.3) Miscellaneous, 2 (4.3) Pleural effusion, 2 (1.2) Pleuritis, 1 (0.6) Atelectasis, 1 (0.6) Pneumothorax, 2 (1.2) Intercostal neuralgia, 9 (5.4) CSF leak, 1 (0.6) Dural tear, 1 (0.6) Residual disc, 3 (1.8) Neurological impairment, 3 (1.8) Miscellaneous, 3 (1.8) Pleuritis, 1 (9.1) Pleural effusion, 6 (5.0) Dural tear, 2 (1.7) Cardiovascular, 1 (0.8) Reintubation, 3 (2.5) Residual disc, 2 (1.7) Miscellaneous, 8 (6.6) Pleural effusion, 1 (33.3) Intercostal neuralgia, 1 (33.3) Venous thrombosis, 1 (20.0) Subcutaneous emphysema, 1 (20.0)
CSF = cerebrospinal fluid.
disease (1.1%) [1,12,17]. There was no reported mortality attributed to this procedure. 3.3. Outcomes The average postoperative follow-up period was 20.5 months (range: 12–48). Resolution or improvement of the presenting symptoms was reported in 79% of the patients, 9.5% reported that their symptoms did not change, and 11% reported worsening of symptoms. Kim et al. [19] and Sasani et al. [20] reported a change in the visual analog scale for pain evaluation from 7.5 to 1.5 and from 8.7 to 1.9, respectively, at the end of the follow-up period. The American Spinal Injury Association score was reported to have
improved postoperatively in two articles [17,22]. Anand et al. [12] reported an average improvement in the Oswestry disability index (ODI) score of 60% for Grade 4 patients, 37% for Grade 3A, 28% for Grade 3B, and 24% for Grade 1. Sasani et al. [20] reported an improvement in their patients in the average ODI from 88.3% preoperatively to 24.5% by the end of a mean follow-up of 24 months (Table 5).
4. Discussion Nearly 94% of thoracic herniated discs are in the midline [24], necessitating an anterolateral approach to the pathology. These are performed through a thoracotomy, which allows for a wider surgical field with less manipulation of the spinal cord and a lower risk of neurological deterioration. However, anterior thoracotomy is associated with significant morbidity and may be difficult to justify, particularly for patients with only mild symptoms. The approach necessitates a large skin incision, lung collapse and retraction, and rib resection with the assistance of an approach surgeon. This can contribute to postoperative pulmonary dysfunction and pain, and prolonged hospital stays. Thoracotomy to treat thoracic herniated discs has an average complication rate of 11.5% [25]. Although advancements have been made in transthoracic approaches over the course of 60 years, recent data from Wait et al. suggest that the complication rate is still as high as 28%, with 15.4% of patients suffering from pulmonary complications [1]. The advent of thoracoscopic approaches for cardiothoracic disease has fostered the development of minimally invasive approaches for ventral thoracic spinal disease. Here, we report the largest systematic review to date of this relatively novel surgical approach. Our data suggest that thoracoscopic discectomy provides excellent clinical results with acceptable rates of morbidity and mortality when performed by an experienced surgeon in properly selected patients.
4.1. Advantages Our systematic review highlights the multiple advantages that thoracoscopy has over open thoracotomy. Open surgery can have a significant rate of intercostal neuralgia, ranging from 7.1% to as high as 50% [8,26]. MIT has an intercostal neuralgia rate of 6.2%, which is likely attributable to the smaller surgical incision and the lack of need for a rib resection or retraction. The thoracoscopic approach offers a reduction in pain due to decreased chest wall injury, as compared with open thoracotomy which is often associated with postthoracotomy syndrome. This syndrome may resolve over several years or, in some patients, become permanent [25]. The pulmonary complications in open transthoracic surgery ranged from 3.4–41% in the literature [1,8,25,26]. Our systematic review demonstrated a pulmonary complication rate of 7.9%, which includes complications such as pleural effusions, pneumonia, atelectasis, pneumothorax, and pleuritis. This rate is comparable with open surgery, since both procedures require single lung deflation on the ipsilateral side and single lung ventilation [27]. In our systematic review, there were 22 reoperations, six of which were performed with open surgery. Five of these reoperations were to remove residual discs, mostly from an intradural location which required additional vertebral body resection. The remaining reoperations were for a misidentified level, dural tears, and spinal instability. None of these procedures necessitated an open surgical bailout. The low frequency of reoperation demonstrates the effectiveness of the thoracoscopic approach in removing symptomatic thoracic herniated discs. These results suggest that,
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
5
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx Table 5 Outcome and follow-up of minimally invasive thoracic discectomy Study
Patients, n Presenting symptoms, n (%)
Follow-up
Follow-up, monthsa
Anand et al., 2002 [12]
100
Predominant axial pain, 28 (28) Thoracic radicular pain, 5 (5) Axial and thoracic radicular pain, 38 (38) Axial and lower leg pain with or without thoracic radicular pain, 19 (19) Myelopathy, 8 (8) Paretic-paralytic, 2 (2)
ODI: Average improvement by grade, Grade 4 (60%), Grade 3A (37%), Grade 3B (28%), Grade 1 (24%)
Bartels et al., 2007 [16]
7
Myelopathy with gait disturbances, 6 (86) Frankel Grade: Preop 1C and 6D, 6 weeks postop 4D and 3E, Mixed, 1 (14) last follow-up 3D and 4E
13
Gille et al., 2006 [17]
18
Myelopathy, 18 (100)
ASIA score improved in three patients, tone improved in all, mean VAS score 1.5
12
Kasliwal and Deutsch, 2011 [18] 7
Myelopathy, 3 (43) Mixed pain, 4 (57)
Nurick scale: three patients improved by 1 point
16
Kim et al., 2007 [19]
3
Radiculopathy, 1 (33) Myelopathy, 2 (67)
VAS score improved from 7.5 to 1.5
15
Mack et al., 1995 [13]
57
N/A
49 (86%) with total relief of symptoms, 23 (40%) with total relief of pain, 26 (46%) with moderate to marked relief of symptoms, 8 (14%) with no improvement
Oskouian et al., 2005 [14]
46
Radiculopathy, 21 (46) Myelopathy, 25 (54)
Improvement in myelopathy by a mean of two Frankel grades in 18 (40%), unchanged in 27 (59%), 1 worsened; improvement of radiculopathy with ODI from 60 to 14 in 75%
12
Quint et al., 2012 [15]b
167
Radiculopathy, 80 (52.3) Low back pain, 16 (10.4) Combined pain, 57 (37)
48 (31%) excellent, 73 (48%) good, 26 (17%) regular, 6 (4%) poor results
24
Sasani et al., 2011 [20]
11
Low back pain, 8 (73) Back pain with paresthesia, 3 (27)
VAS score: 8.7 (preop), 4.7 (3 month postop), 2.8 (6 month postop), 1.8 (12 month postop), 1.9 (24 month postop); ODI: 88.3 (preop), 40.1 (3 month postop), 37 (6 month postop), 26.3 (12 month postop), 24.5 (24 month postop)
24
Wait et al., 2012 [1]c
121
Radiculopathy, 46 (43) Myelopathy, 35 (28.9) Combined pain, 33 (27.2) Low back pain, 2 (2)
Radiculopathy:67 (83.8%) complete resolution, 11 (13.8%) improvement, 1 (1.2%) no change, 1 (1.2%) worsened; Myelopathy: 50 (73.5%) reduction, 18 (26.5%) no change, 1 (1.5%) worsened; Back pain: 21 (56.8%) complete resolution, 11 (29.7%) improvement, 5 (13.5%) no change in back pain
29
Yanni et al., 2011 [22]
5
Myelopathy, 1 (20) Left extremity weakness and gait difficulty/axial pain, 1 (20) Midthoracic pain, 1 (20) Proximal leg weakness, 1 (20) Axial pain with girdling pain, 1 (20)
Nurick scale: 1 point improvement in three patients; ASIA: 1 letter improvement in two patients
12
48
N/A
ASIA = American Spinal Injury Association, N/A = not available, ODI = Oswestry disability index, postop = postoperative, preop = preoperative, VAS = visual analog scale. a Last follow-up. b Presenting symptom information was not available for all patients in the study. c Patients may have had one or more symptoms with varying outcomes by symptom.
for the appropriately selected patient, thoracoscopy maintains the advantages of anterior surgery with comparable rates of pulmonary complications and reduced rates of intercostal neuralgia. Our review also indicates that minimally invasive thoracoscopic approaches to treat thoracic herniated discs have excellent clinical results. We found that only 1.2% of patients had worsened symptoms that were not resolved at last follow-up, 9.6% had no improvement in symptoms, 10.2% had improved but residual symptoms, and 79% had complete resolution of symptoms over an average follow-up of 20.5 months. 4.2. Disadvantages While our data support the use of thoracoscopy, proper patient selection is critical to avoid reoperation, conversion to open surgery, and surgical complications. Symptomatic patients may have thoracic discs that are large, calcified, transdural, and adherent to the dura. In one study that evaluated the clinical and surgical outcomes of patients with giant herniated discs (those occupying 40% of the diameter of the spinal cord), the authors determined that thoracotomy is better suited for the removal of calcified giant
thoracic herniated discs, while thoracoscopy is better suited for soft giant thoracic herniated discs. When discs were ossified, transdural, and massive, the authors reported a switch from thoracoscopy (n = 4) to open surgery to minimize any compression of the spinal cord during resection of the mass [1]. Overall, the literature indicates that thoracoscopy is better suited for soft thoracic discs. Although they were rare complications in our analyses, dural tears and CSF leaks did occur. The requirement of reoperations can be avoided by using an open approach to treat intradural ossified thoracic herniated discs. The open approach affords the surgeon more precise bimanual dexterity which is necessary for water-tight dural closure [28]. Additionally, there are reported contraindications to a minimally invasive procedure that may lower the complication rate further. Wait et al. included preexisting pleural disease, pleural symphysis, previous thoracotomy due to possible pleural adhesions, and inability to tolerate single lung ventilation as relative contraindications [1]. Additionally, thoracoscopy can be used from T1 to T12 to treat multiple pathologies, but our group previously found that levels T1–4 and T11–L1 may be more appropriately accessed via a non-endoscopic approach [1].
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013
6
A.M. Elhadi et al. / Journal of Clinical Neuroscience xxx (2015) xxx–xxx
A final consideration in thoracoscopic discectomy is the relatively steep learning curve for surgeons. The specific endoscopic instrumentation, 2D endoscopic images, and operating through a small opening to reach the spine at a longer distance and greater angle, are unique to endoscopy and may not be intuitive to surgeons who are accustomed to open procedures [1,19]. Our institution previously reported an initial complication rate of 28.6% that declined to 5.3% in the first 9 years of experience [1]. This trend is also demonstrated by the reduction in overall complication rates in each study as the number of patients who underwent the procedure increased. This suggests that many of the complications reported in this series may be prevented with improved training and surgical experience, in addition to improved patient selection, as previously mentioned. 5. Conclusion Thoracoscopic spinal surgery is a safe and effective alternative for thoracic discectomy in a properly selected subset of patients, and in the hands of an experienced surgeon. Our results and personal experience indicate that thoracoscopic discectomy should be the preferred treatment in soft, centrally located thoracic discs between T4 and T11 because of the less invasive nature of the procedure and the reduced rate of intercostal neuralgia. Open thoracotomy is indicated for large calcified or intradural disc herniations and other thoracic levels. Overall, with appropriately selected patients and proper surgical training, thoracoscopy maintains the advantages of anterior surgery, with comparable rates of pulmonary complications, reduced rates of intercostal neuralgia, and, most importantly, improved patient outcomes as compared to open surgery. Future prospective trials with long term follow-up data are necessary to truly assess the clinical efficacy of this approach. Conflicts of Interest/Disclosures The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication. References [1] Wait SD, Fox Jr DJ, Kenny KJ, et al. Thoracoscopic resection of symptomatic herniated thoracic discs: clinical results in 121 patients. Spine (Phila Pa 1976) 2012;37:35–40. [2] Carson J, Gumpert J, Jefferson A. Diagnosis and treatment of thoracic intervertebral disc protrusions. J Neurol Neurosurg Psychiatry 1971;34:68–77. [3] Beisse R. Endoscopic surgery on the thoracolumbar junction of the spine. Eur Spine J 2006;15:687–704. [4] Burke TG, Caputy AJ. Treatment of thoracic disc herniation: evolution toward the minimally invasive thoracoscopic technique. Neurosurg Focus 2000;9:e9.
[5] Jho HD. Endoscopic transpedicular thoracic discectomy. Neurosurg Focus 2000;9:e4. [6] Lidar Z, Lifshutz J, Bhattacharjee S, et al. Minimally invasive, extracavitary approach for thoracic disc herniation: technical report and preliminary results. Spine J 2006;6:157–63. [7] Regev GJ, Salame K, Behrbalk E, et al. Minimally invasive transforaminal, thoracic microscopic discectomy: technical report and preliminary results and complications. Spine J 2012;12:570–6. [8] Rosenthal D. Endoscopic approaches to the thoracic spine. Eur Spine J 2000;9:S8–S16. [9] Landreneau RJ, Hazelrigg SR, Mack MJ, et al. Postoperative pain-related morbidity: video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56:1285–9. [10] Sheikh H, Samartzis D, Perez-Cruet MJ. Techniques for the operative management of thoracic disc herniation: minimally invasive thoracic microdiscectomy. Orthop Clin North Am 2007;38:351–61 [abstract vi]. [11] Bohlman HH, Zdeblick TA. Anterior excision of herniated thoracic discs. J Bone Joint Surg Am 1988;70:1038–47. [12] Anand N, Regan JJ. Video-assisted thoracoscopic surgery for thoracic disc disease: classification and outcome study of 100 consecutive cases with a 2year minimum follow-up period. Spine (Phila Pa 1976) 2002;27:871–9. [13] Mack MJ, Regan JJ, McAfee PC, et al. Video-assisted thoracic surgery for the anterior approach to the thoracic spine. Ann Thorac Surg 1995;59:1100–6. [14] Oskouian RJ, Johnson JP. Endoscopic thoracic microdiscectomy. J Neurosurg Spine 2005;3:459–64. [15] Quint U, Bordon G, Preissl I, et al. Thoracoscopic treatment for single level symptomatic thoracic disc herniation: a prospective followed cohort study in a group of 167 consecutive cases. Eur Spine J 2012;21:637–45. [16] Bartels RH, Peul WC. Mini-thoracotomy or thoracoscopic treatment for medially located thoracic herniated disc? Spine (Phila Pa 1976) 2007;32:E581–4. [17] Gille O, Soderlund C, Razafimahandri HJ, et al. Analysis of hard thoracic herniated discs: review of 18 cases operated by thoracoscopy. Eur Spine J 2006;15:537–42. [18] Kasliwal MK, Deutsch H. Minimally invasive retropleural approach for central thoracic disc herniation. Minim Invasive Neurosurg 2011;54:167–71. [19] Kim SJ, Sohn MJ, Ryoo JY, et al. Clinical analysis of video-assisted thoracoscopic spinal surgery in the thoracic or thoracolumbar spinal pathologies. J Korean Neurosurg Soc 2007;42:293–9. [20] Sasani M, Fahir Ozer A, Oktenoglu T, et al. Thoracoscopic surgery for thoracic disc herniation. J Neurosurg Sci 2011;55:391–5. [21] Watanabe K, Yabuki S, Konno S, et al. Complications of endoscopic spinal surgery: a retrospective study of thoracoscopy and retroperitoneoscopy. J Orthop Sci 2007;12:42–8. [22] Yanni DS, Connery C, Perin NI. Video-assisted thoracoscopic surgery combined with a tubular retractor system for minimally invasive thoracic discectomy. Neurosurgery 2011;68:138–43 [discussion 143]. [23] Hott JS, Feiz-Erfan I, Kenny K, et al. Surgical management of giant herniated thoracic discs: analysis of 20 cases. J Neurosurg Spine 2005;3:191–7. [24] Stillerman CB, Chen TC, Couldwell WT, et al. Experience in the surgical management of 82 symptomatic herniated thoracic discs and review of the literature. J Neurosurg 1998;88:623–33. [25] Fessler RG, Sturgill M. Review: complications of surgery for thoracic disc disease. Surg Neurol 1998;49:609–18. [26] McCormick WE, Will SF, Benzel EC. Surgery for thoracic disc disease. Complication avoidance: overview and management. Neurosurg Focus 2000;9:e13. [27] Lall RR, Smith ZA, Wong AP, et al. Minimally invasive thoracic corpectomy: surgical strategies for malignancy, trauma, and complex spinal pathologies. Minim Invasive Surg 2012;2012:213791. [28] Perez-Cruet MJ, Fessler RG, Perin NI. Review: complications of minimally invasive spinal surgery. Neurosurgery 2002;51:S26–36.
Please cite this article in press as: Elhadi AM et al. Surgical efficacy of minimally invasive thoracic discectomy. J Clin Neurosci (2015), http://dx.doi.org/ 10.1016/j.jocn.2015.05.013