Accepted Manuscript Fully Endoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-term Clinical Results of 163 Surgically Treated Patients Altay Sencer , MD Ali Guven Yorukoglu , MD Mehmet Osman Akcakaya , MD Yavuz Aras , MD Aydin Aydoseli , MD Osman Boyali , MD Fahir Sencan , MD Pulat Akin Sabanci , MD Cengiz Gomleksiz , MD Murat Imer , MD Talat Kiris , MD Kemal Hepgul , MD Omer Faruk Unal , MD Nail Izgi , MD Ali Tuncay Canbolat , MD PII:
S1878-8750(14)00539-7
DOI:
10.1016/j.wneu.2014.05.032
Reference:
WNEU 2387
To appear in:
World Neurosurgery
Received Date: 14 September 2013 Revised Date:
7 December 2013
Accepted Date: 29 May 2014
Please cite this article as: Sencer A, Yorukoglu AG, Akcakaya MO, Aras Y, Aydoseli A, Boyali O, Sencan F, Sabanci PA, Gomleksiz C, Imer M, Kiris T, Hepgul K, Unal OF, Izgi N, Canbolat AT, Fully Endoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-term Clinical Results of 163 Surgically Treated Patients, World Neurosurgery (2014), doi: 10.1016/j.wneu.2014.05.032. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Fully Endoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-term Clinical Results of 163 Surgically Treated Patients
Altay Sencer MD1, Ali Guven Yorukoglu MD2, Mehmet Osman Akcakaya MD3, Yavuz Aras
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MD1, Aydin Aydoseli MD1, Osman Boyali MD1, Fahir Sencan MD1, Pulat Akin Sabanci MD1, Cengiz Gomleksiz MD4, Murat Imer MD1, Talat Kiris MD1, Kemal Hepgul MD1, Omer Faruk
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Unal MD1, Nail Izgi MD1, Ali Tuncay Canbolat MD1
1) Department of Neurosurgery, Istanbul School of Medicine, Istanbul University,
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Istanbul/ Turkey
2) Department of Neurosurgery, Artvin State Hospital, Artvin/Turkey 3) Department of Neurosurgery, Taksim Training and Research Hospital, Istanbul/Turkey
Erzincan/Turkey
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Corresponding Author:
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4) Department of Neurosurgery, Erzincan University Faculty of Medicine,
Mehmet Osman Akcakaya, MD
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Taksim Egitim ve Arastırma Hastanesi, Nöroşirürji Kliniği Sıraselviler Cad. No:112 Beyoglu/Istanbul 34433 E-mail:
[email protected] Phone: 00905322557774 Keywords: endoscopic discectomy, transforaminal discectomy, interlaminar discectomy, percutaneous discectomy, lumbar disc herniation, minimally invasive spine surgery Running Head: Sencer et al, Fully Endoscopic Lumbar Discectomy
ACCEPTED MANUSCRIPT Abstract:
Objective: Due to technical advances, minimally invasive surgical techniques are becoming increasingly common in an attempt to decrease tissue trauma. In this study, we evaluated the
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clinical outcomes of lumbar disc disease patients undergoing fully endoscopic surgery at our clinic.
Methods: One hundred sixty-three patients underwent fully endoscopic lumbar discectomy
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between August 2009 and January 2012. There were 74 male and 89 female patients in our study. All patients were followed for one year after surgery. The Oswestry Disability Index
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(ODI) and the visual analog scale (VAS) were used to analyze outcomes.
Results: During the follow-up period, 114 (70%) patients had no complaints, 30 (18%) patients had occasional pain, and 19 (12%) had no improvement. During postoperative follow-up, eight patients required repeat surgery due to recurrence or residual fragments.
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Postoperatively, four patients experienced dysesthesia, which completely resolved in time. Five patients deteriorated neurologically, four of whom recovered completely without any intervention. Dural tears occurred in six patients.
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Conclusions: The results of our study show that fully endoscopic interlaminar or transforaminal surgeries are safe and effective treatment modalities for lumbar disc
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herniations. As our clinical experience indicates, despite the difficulties of acquiring this new technique, good results can be achieved with sufficient experience.
Keywords: endoscopic discectomy, transforaminal discectomy, interlaminar discectomy, percutaneous discectomy, lumbar disc herniation, minimally invasive spine surgery
ACCEPTED MANUSCRIPT Introduction:
Since the first description of the open lumbar discectomy by Dandy, followed by Mixter and Barr (9,34), significant improvements have been achieved in the management of
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lumbar disc herniation. After the introduction of the surgical microscope, Caspar (7) and Yasargil (52) defined laminectomy and open microdiscectomy (MD). This technique, with slight variations, has become the standard surgical procedure for lumbar disc herniations
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through the last decade and is still the predominant surgical approach.
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In the past three decades, minimally invasive surgery has attracted increasing attention. With the evolution and refinement of the surgical endoscope, minimally invasive endoscopic surgical techniques have been widely adopted in different fields of medicine. However, compared to other surgical fields such as gastrointestinal or orthopedic surgery,
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endoscopes have been slow to gain widespread application in spinal surgery. Minimally invasive procedures in the lumbar spine date back to 1948, when Valls et al. described a percutaneous technique for aspiration biopsy of vertebral body lesions. (48) In the 1970s,
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Hijikata (17) and Kambin (21) separately defined a posterolateral approach for percutaneous central nucleotomy. Forst and Housmann first visualized the intervertebral disc space with a
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modified arthroscope. (15) Mayer, Schreiber and Kambin improved endoscopic lumbar discectomy techniques. (16,23,33,44,45) In particular, Kambin’s anatomic description of the neural foramen for the purposes of endoscopic access was one of the cornerstones in the development of a fully endoscopic transforaminal approach. Major improvements were achieved by the introduction of the “Yeung Endoscopic Spine System (YESS)” by Yeung (53,55) and the fully endoscopic interlaminar technique described by Ruetten. (40) Today,
ACCEPTED MANUSCRIPT endoscopic lumbar discectomy has become an important alternative to conventional MD in the management of lumbar disc herniations.
Various surgical techniques have been described; however, minimally invasive
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endoscopic approaches to the lumbar spine can be classified into two major categories: transforaminal (TF) and interlaminar (IL). TF approaches can be divided into fully endoscopic posterolateral and lateral subcategories. IL approaches can be categorized as endoscopy-
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assisted techniques or fully endoscopic techniques.
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This prospective study presents the surgical results of 163 patients with lumbar disc herniations who underwent surgery using both fully endoscopic IL and lateral TF approaches. The indications and limitations of both approaches are described, and the possible difficulties and complications that may be faced by surgeons who are unfamiliar with these procedures
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are presented. The aim of this study is to present our experience with fully endoscopic lumbar discectomy in an effort to evaluate our clinical results, specifically in terms of the safety and
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efficacy of this approach.
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Patients and Methods:
Patient Demographics and Diagnoses
One hundred sixty-three consecutive patients who underwent fully endoscopic lumbar discectomy (FELD) in our department between August 2009 and January 2012 were evaluated in this study. One hundred seventy-five disc levels were operated upon, as multiple
ACCEPTED MANUSCRIPT level lumbar discectomy was performed in 11 patients. There were 74 male and 89 female patients. The mean age was 47 years (range 18 to 78 years). All patients had experienced ongoing symptoms of back and leg pain. The indications for surgery were the same as for open microsurgery, namely, the presence of any progressive neurological deficit or radicular
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pain that was unresponsive to medical therapy. Only patients with cauda equina syndrome did
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not undergo endoscopic surgery.
Magnetic resonance imaging (MRI) was performed in all cases. An additional
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abdominal computed tomography (CT) scan was performed in order to visualize the anatomical structures and to prevent retroperitoneal injuries related to the lateral access
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techniques used by the TF approach for lumbar disc herniations above the L3-4 level.
Selection Criteria for Surgical Approach
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The selection of a lateral TF versus an IL approach was based on the principles previously defined by Ruetten et al. (39,41,42) The TF approach was the first choice, but it
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has known anatomic limitations. Therefore, the IL approach was chosen in patients with the following characteristics: a) sequestering material had migrated beyond the lower edge of the cranial pedicle or over the middle of the caudal pedicle, and b) the foramen was overlaid by the iliac crest on lateral plain radiographs. (39,41,42)
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Surgical Technique
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We used the same surgical techniques for both approaches that were previously described by Ruetten et al. (38-42) Operations are performed under general anesthesia. The patient is placed on the operating table in the prone position. The c-arm is positioned under
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the operating table to allow sterile biplanar fluoroscopic control. For both approaches, the skin
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incision is first marked. Following marking, the skin and muscle fascia incisions are made.
Normally, in the TF approach, the skin incision is located 8-12 cm from the midline, but for the lateral TF approach, it must be located more laterally, depending on individual anatomy. The purpose is to obtain tangential access to the spinal canal. (Figure 1) As viewed
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on lateral fluoroscopy, the posterior edge of the inferior articular process limits the entry zone anteriorly for levels L3-4 and below. For levels above L3-4, care must be taken in order to avoid damage to abdominal and thoracic anatomical structures. As mentioned above, an
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additional abdominal CT may be a useful tool for planing the entry approach. Under fluoroscopic control, a 1.5-mm blunt spinal cannula is inserted; through this, a 0.8 mm
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guidewire is then inserted. The cannula is removed, and a cannulated dilator (with an outer diameter of 6.9 mm) is inserted using the guidewire. The guidewire is then removed, and with this blunt dilator, the position can be fixed more safely under fluoroscopic control. A surgical sheath (with an outer diameter of 7.9 mm) with a beveled opening is placed over the dilator. Then, using a direct endoscopic view and continuous irrigation, decompression is performed (as shown in Figure 2 and 4a). Cauterization of the surrounding soft tissues allows hemostasis and a cleaner surgical view. Decompression of the disc space and subsequent exploration of
ACCEPTED MANUSCRIPT the posterior longitudinal ligament (PLL) and the epidural space for the herniated disc is more useful than directly searching for the sequestering material. Free fluctuation of the PLL under constant irrigation is a good indicator of an adequate decompression.
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The skin incision for the IL approach is made as medial to the midline of the targeted interlaminar space as possible. Again, the dilator (with an outer diameter of 6.9 mm) is bluntly inserted under fluoroscopic control to the lateral edge of the interlaminar space, and
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the surgical sheath (with an outer diameter of 7.9 mm) with a beveled opening is placed over the dilator. The procedure is continued using a direct endoscopic view and continuous
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irrigation. Following cauterization and resection of the surrounding soft tissues, the ligamentum flavum is exposed and is laterally incised for 3 to 5 mm. This incision can be enlarged if necessary. After accessing the spinal canal, the dura mater and nerve roots are exposed (Figure 3). The beveled opening of the surgical sheath can be used as a nerve root
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retractor by rotating it. Following cauterization of the epidural veins, discectomy is performed under fluoroscopic control (Figure 4b). If the bony structures do not allow enough access to the spinal canal, further bone resection can be performed using a burr or Kerrison rongeur.
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Compared to the TF approach, the IL approach is a more mobile access, allowing the visualization of neighboring levels by using the endoscope like a joystick. With the IL
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approach, bony resection can be achieved as necessary, and caudally or cranially migrated disc herniations can be treated.
Outcome Assessment
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If no complications occurred, patients were mobilized three hours after the operation, and they were discharged from the hospital the next day. An early follow-up examination was performed three weeks after surgery. The patients also returned for follow-up visits at 3, 6, 9,
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and 12 months after surgery. Pre- and postoperative visual analog scale (VAS) testing and the Turkish version of the “Oswestry Disability Index” (ODI) were used to evaluate clinical outcomes and pain relief. (12) Additionally, a telephone interview was performed that
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included questions assessing the subjective satisfaction of the patients. Clinical follow-up examinations and interviews were performed by three physicians who were not involved in
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the operations.
Statistical Analysis
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The t-test was used to compare pre- and postoperative VAS and ODI scores. Descriptive assessments and analytical statistics were calculated, depending on the group’s
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less than 0.05.
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characteristics, using SPSS 16. A positive significance level was assumed at a probability of
Results:
In 163 patients, a total of 175 FELDs were performed. One hundred and four patients (59.5%) underwent surgery using the IL approach, and 71 patients (40.5%) underwent surgery using the lateral TF approach. Patients with no complications (91%) were mobilized three hours postoperatively and were discharged from the hospital the next day. The majority of the
ACCEPTED MANUSCRIPT operations were performed on the L4-5 (93 cases - 53%) and L5-S1 (52 cases – 30%) levels. The follow-up time was 12 months. The distribution of the herniated disc levels and surgical approaches are summarized in Table 1.
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Multi-level lumbar discectomy was performed in 11 patients, and single-level discectomy was performed in 152 patients. Three-level discectomy was performed in one case, and in 10 cases two-level discectomy was performed. Eleven cases with single-level disc
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herniations had a history of previous MD at the same level and the same side. The TF approach was used in four of these patients, and the IL approach was performed in seven
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patients. (L5-S1: 3 IL/1 TF, L4-5: 2 IL/2 TF, L3-4: 1 IL, L2-3: 2 TF) Pain relief was achieved in all of these 11 patients.
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Reoperations
The herniated disc material was removed in all cases. Intraoperative conversion to conventional MD was not required in our cases. In two cases (1.2%), early pain relief did not
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occur; both of these patients underwent surgery via the lateral TF approach. With further radiological evaluation, the presence of residual herniated disc material was identified, and
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these patients underwent reoperation with the same technique. Pain relief was achieved in one of these cases. The other patient did not experience significant improvement.
There were 6 recurrences (3.7%) among our patients. Following a pain-free interval, the mean time from the first operation to recurrence was 1.5 months in our series (range 2 weeks to 3 months). The primary surgical approach was IL in four cases and TF in two cases. Four of these recurrences underwent repeat surgery using the technique described here, and in
ACCEPTED MANUSCRIPT two cases (one IL and one TF), conventional MD was the preferred approach for reoperation. No further recurrences occurred following the second surgery. In four of these cases, good pain control was achieved, whereas in two cases (where the IL approach was used for both the initial and repeat operations), no significant improvement was noted. The distribution of
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lumbar disc herniation levels, selected surgical approaches for the initial and the second operations, time to the second operation, and outcomes are summarized in Table 2.
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Complications
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Motor deficits occurred in five patients (3%). Most of these deficits occurred in the early cases of this series and were attributed to possible nerve root injuries due to nerve root retraction. In two of these cases, two-level discectomy was performed using an IL approach for one level and a TF approach for the other. In four cases, these motor deficits were
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transient, and complete recovery occurred, including the two patients who underwent twolevel discectomies. In only one case (0.6%), there was a permanent postoperative motor
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deficit, resulting in “foot drop”.
Four patients experienced dysesthesia after the surgery (2.4%). All of the patients who
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developed dysesthesia underwent surgery via the TF approach. Limited relief was achieved in one patient with epidural and foraminal steroid injections. In the other three cases, this complaint resolved completely.
Dural tears occurred in six cases (3.6%), but open cerebrospinal fluid (CSF) fistula occurred in only one of these patients (0.6%). All the patients who experienced dural tears underwent surgery with the IL approach. There was no attempt at dural repair in five cases; no
ACCEPTED MANUSCRIPT open or closed CSF fistula occurred in these cases, probably because of the small surgical incision. These patients were followed up in the clinic with two additional days of bed rest and thereafter were mobilized and discharged. The single case of an open CSF fistula was the first case in our series in which this complication occurred. Unfortunately, we attempted to
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repair the dura using an open microsurgical technique immediately after completing the FELD. This patient had to undergo a second surgery for dural repair, and the fistula was managed with 5 days of bed rest and lumbar drainage. There were no reports of infection,
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secondary spondylodiscitis or abdominal organ injury in our series, except for two superficial wound infections (1.2%), which were managed with oral antibiotics. Complications are
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summarized in Table 3.
Clinical Outcomes
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The bar graphs in Figure 5 show the differences in VAS and ODI scores before surgery and at 12 months after surgery. Preoperatively, most of the patients had severe pain, rendering them unable to perform their daily activities. As a result, the mean preoperative
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VAS and ODI scores were 8,07/10 and 37,04, respectively. There was a significant decrease in both the VAS and ODI scores after the FELD (p< 0,001). With a follow-up time of 12
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months, 114 patients (70%) claimed that they no longer had leg pain, 30 patients (18%) had occasional leg pain with general pain relief, and 19 patients (12%) experienced no significant improvement. There were no persisting symptoms following revision surgeries for recurrent or residual lumbar disc herniations. One hundred thirty-eight patients (85%) had subjective satisfaction and would undergo the FELD operation again.
Discussion
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Today, MD remains the standard surgical treatment for lumbar disc herniation. Nevertheless, endoscopic surgical techniques have gained considerable attention in various fields of surgery and have replaced conventional approaches in the management of many diseases,
especially
in
gastrointestinal,
orthopedic,
thoracic
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different
and
otorhinolaryngological surgery. However, endoscopic neurosurgical techniques, particularly for spine surgery, have been slow to gain acceptance. This may be due to the high success rate
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of MD (between 75% and 100%; 2,11,13,28,51) and the routine use of microsurgical techniques in nearly every field of neurosurgery. With such a high success rate, it is hard to
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convince neurosurgeons who already have microsurgical skills to learn the endoscopic lumbar discectomy technique, which is known for its steep learning curve. (20,31,36,43) Additionally, the reported failure rates (20,26,31,32,43), the need of additional surgical time (37), the need of strict patient selection (35) and potential complications cut in favor of
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skeptics.
Lumbar disc herniation is a major health problem, and successful surgical treatment of
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this condition is crucial in order to allow individuals to remain in the work force. Minimally invasive lumbar disc surgery has attracted growing attention because of a possible reduction
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in postoperative pain, earlier mobilization and a shorter recovery period. Although no studies have provided Level 1 evidence for these advantages of minimally invasive procedures, many studies, including ours, have shown that minimally invasive surgical treatment of lumbar disc herniation provides comparable results to the classical surgical approaches. In a study by Ruetten et al., no significant differences in clinical results were noted between FELD (IL or lateral TF) and MD. (42) The main advantages of FELD include decreased operative trauma and reduced epidural scarring (due to the use of an 8-mm cannula and direct visualization and
ACCEPTED MANUSCRIPT illumination), early postoperative mobilization of patients, and reduced overall costs. (41,42) In contrast to other publications, shorter operating times and success rates as high as conventional MD have been reported in recent studies. (40,42) However, these studies were conducted at a single institution and may be subject to biases related to patient selection, lack
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of randomization, and subjective observations. Nellensteijn et al. provide a thorough review of all studies related to the endoscopic lumbar disc surgery using the lateral TF approach. (35) Thirty-nine different studies were analyzed; serious design weaknesses and a high risk of
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selection bias were found in most of these. (35) Such criticisms also apply to the IL approach. Given the current literature, objectively drawing such conclusions is not possible, due to a
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previously noted lack of Level 1 evidence. Due to a lack of data from patients who underwent MD at our institution prior to this study and a very small number of patients who underwent MD during the study period, we did not conduct a study aiming to compare the surgical results of MD and FELD. This is another weakness of our study. However, our fairly large
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series provides some information to surgeons who want to adopt this technique in their clinical practice. Despite the lack of Level 1 evidence, we still believe that minimally invasive lumbar disc surgery will become a better alternative to classical surgical techniques, due to
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the aforementioned advantages which, although subjective, may be preferred both by patients
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and health insurance systems.
At our institution, we have been operating on lumbar disc herniations using an endoscopic approach since 2009. Either the lateral TF or IL routes have been used, depending on the characteristics of each individual case. Due to minimal tissue retraction, the lateral TF approach is the preferred minimally invasive approach, if possible. However, the TF approach is not preferred when the sequestering material has migrated beyond the lower edge of the cranial pedicle or over the middle of the caudal pedicle, or in cases where the neural foramen
ACCEPTED MANUSCRIPT is overlaid by the iliac crest on lateral plain radiographs. Due to the position of the iliac crest, most of the L5-S1 herniations (49/52) and approximately half of the herniations at the L4-5 level (49/93) in our series were treated using the IL technique. The cranial or caudal migration
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of the sequestering material was more decisive for cases above the L4-5 level.
For neurosurgeons who are experienced in conventional MD, the IL approach is easier to adopt because of similarities in the anatomic orientation. However, the lateral TF approach
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may be more demanding. The initial stage of spinal cannula insertion under fluoroscopy is of the utmost importance, as it leads the surgeon to the optimal target point. Failures at that stage
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may result in improper placement of the endoscope, creating a risk of nerve root injury and inability to remove the herniated disc. Transforaminal steroid injection is a common method used in the management of radicular pain. (4) Like several other authors (31), we recommend that all neurosurgeons who wish to use the TF approach perform transforaminal epidural
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steroid injections, due to the similarity between the injection procedure and the initial step of the TF approach. Another good training opportunity is working on cadavers in order to
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improve endoscopic surgical skills.
Another serious complication of the lateral TF approach is visceral organ or vascular
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injury. Even minor manipulation failures while using the spinal cannula may cause contact with the contents of the abdominal organs and, consequently, infections. Psoas abcess and spondylodiscitis following TF procedures have previously been reported. (27) To avoid these injuries, abdominal CT scans may assist in the visualization of anatomical structures in order to calculate a safe entrance trajectory.
ACCEPTED MANUSCRIPT The IL approach is similar to conventional MD; however, anatomic orientation can easily be lost with misplacement of the working sheath. (49) If the sheath is placed too far laterally or medially, placement confusion may occur, complicating the identification of anatomic structures and leading to prolonged operation times and iatrogenic injuries.
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Additionally, inappropriate manipulation of the neural elements may result in transient or permanent motor deficits. (49)
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Good clinical results have been reported for endoscopic discectomies, even with various TF and IL approaches, different patient selection criteria, and varying surgical
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techniques. (1,8,10,14,19,22,24,25,39-41,47,53-56) The overall success rate for conventional MD ranges from 75% to 100%. (2,11,13,28,51) In our series, the clinical results are consistent with previously published data for both endoscopic and MD surgeries. An 85% subjective patient satisfaction rate 12 months after surgery is a considerably good result, and significant
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improvements were achieved in both the VAS and ODI scores.
The rate of recurrences in our series is 3.7%, which is in accordance with previously
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published data. (3,6,18,30,46,50) Four of these surgeries were performed via the IL approach. Generally, recurrences are attributable to the type of herniation and the size of the annular
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defect. (5,57) Therefore, surgeons should attempt to avoid enlarging the annular defect. A few patients (1/2%) experienced residual disc herniations in our series, which may be related to our lack of experience in the early stages of this study. Both of these surgeries were performed via the TF approach, and repeat surgeries were also performed using the same approach. As mentioned above, for the TF approach, free fluctuation of the PLL under constant irrigation is a good indication of an adequate decompression. The PLL and the
ACCEPTED MANUSCRIPT epidural space should be explored properly in order not to leave any type of free fragments or residual herniation behind.
There were 15 complications (9%) in our series, with only one significant major
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complication (0.6%). Additional motor deficits occurred in five cases (3%), probably related to inadequate use of the beveled opening of the endoscope as a nerve root retractor. Fortunately, in four of these cases, these deficits were only transient, and patients experienced
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complete neurological recovery. In only one case did a permanent motor deficit occur. In two cases with two-level disc herniations, motor deficits occurred postoperatively. In both of these
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cases, TF and IL approaches were used in the same session for different disc levels. Five of the six motor deficits occurred within the first 60 cases of our series, including the case where a permanent deficit occurred and the cases with two-level disc herniations. We believe that the prolonged operative times and increased manipulation of the neural elements for multi–
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level procedures may cause postoperative motor deficits, and therefore we recommend that surgeons gain sufficient experience with single-level FELD before attempting to operate on
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multi-level disc herniations.
Dysaesthesias were encountered in four cases (2.4%), all of which were approached
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with a TF technique. This may be due to the relatively large neural foramen, which allows limited movement of the endoscope. Repeated manipulations and slight movements may result in the irritation of the dorsal root ganglion. Dural tears (3%) are another complication that must be mentioned. All of these surgeries were performed with an IL approach. There was an open CSF fistula in only one case (0.6%), which was related to our attempt to perform a dural repair via an open microscopic approach. In the other five cases, no attempt at dural repair was made; the cases were closed normally, and no open or closed CSF fistulas occurred
ACCEPTED MANUSCRIPT postoperatively. The complication rates in our series are higher than those reported in the series of experienced surgeons. (42) However, our institution had no prior experience with FELD and most of the complications happened in the early stages of this study. Similar complication rates have been reported by various surgeons during the initial stages of using
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this technique. (20, 29, 49)
As our series demonstrates, attention must be paid, especially in the early stages of
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learning this new technique. Inadequate manipulation of nerve roots may result in motor deficits and dural tears, which are primarily related to adhesions that occur secondary to
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chronic herniations. Although dural tears are a major problem in conventional MD, based on our experience, we believe that open or closed CSF fistulas do not readily occur in FELD, probably due to the limited access, which is a possible advantage of this technique. We
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recommend not attempting dural repair if a dural tear occurs.
Conclusions:
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Currently, the goal of surgical treatment for lumbar disc herniations is optimal decompression with minimal tissue trauma and complication. From this perspective, FELD is
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a safe and effective method. Minimal operative trauma and consequent early mobilization and decreased risk of CSF fistula are the advantages of this method. A steep learning curve and possible complications are disadvantages. As our clinical experience indicates, despite the difficulties of learning this new technique, considerably good results may be achieved when enough experience is gained.
ACCEPTED MANUSCRIPT References:
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ACCEPTED MANUSCRIPT 10. Destandau J. [Technical features of endoscopic surgery for lumbar disc herniation: 191 patients.] Neurochirurgie 50: 6-10, 2004 (Article in French) 11. Ebeling U, Reichenberg W, Reulen HJ. Results of microsurgical lumbar discectomy. Review on 485 patients. Acta Neurochir (Wien) 81: 45-42, 1986
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comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. J Bone Joint Surg Am 81: 958-965, 1999 17. Hijakata S. Percutaneous nucleotomy. A new concept technique and 12 years’ experience.
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ACCEPTED MANUSCRIPT Figure Legends:
Figure 1: CT shows calculations for the entry point and entry trajectory for the TF approach in order to provide safe access to the L2-3 disc level in a fresh cadaver. (Used with the
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permission of Burcu Goker, MD, from her unpublished neurosurgery thesis.)
Figure 2: Figure shows the surgeon’s position and the view of the neural foramen from a left lateral TF approach to the L4-5 disc level. The use of continuous irrigation and RF bipolar
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provides a cleaner view (PLL: posterior longitudinal ligament, RF: radiofrequency).
Figure 3: Figure shows the endoscopic view of an IL approach to the L3-4 disc level.
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Figure 4a: Usually, only AP fluoroscopic view is used for the TF approach. Figure shows AP fluoroscopic view of a TF approach to the L4-5 disc level during the disc decompression. Figure 4b: Only lateral fluoroscopic view is used for the IL approach. Figure shows the position of the micropunch within the L4-5 level via IL approach.
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Figure 5: The bar graph shows the differences between pre- and postoperative ODI and VAS
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Acknowledgments:
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scores.
We would like to thank our archive officer, Nurcan Uzel, and our clinical secretaries, Kıymet Gazioglu and Pervin Yuksel, for their help and support.
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Transforaminal
L1 – L2
3
L2 – L3
7
L3 – L4
14
L4 – L5
44
L5 – S1
3
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Total
Interlaminar
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Levels
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Table 1 Total
-
3
3
10
3
17
49
93
49
52
104
175
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Etiology
Levels
1st Op
Time in btw
2nd Op
Outcome
1
Recurrence
L5 - S1
TF
3 months
MD
Better
2
Residual
L4 - L5
3
Recurrence
L4 - L5
4
Recurrence
L5 - S1
5
Recurrence
6
Recurrence
7 8
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Ptn ID
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1 month
TF
Better
IL
2 months
IL
Same
IL
1 week
IL
Better
IL
1 month
IL
Same
L3 - L4
TF
2 months
TF
Better
Recurrence
L5 - S1
IL
2 weeks
MD
Better
Residual
L4 - L5
TF
1 week
TF
Same
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L5 - S1
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n
%
Motor deficits Permanent Transient
1 4
0.6 2.4
Dysesthesia
4
2.4
Dural tear
6
3.6
CSF fistula
1
0.6
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Complication
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Table 3. Complications
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37,04
35,00 30,00 25,00 PreOp
20,00
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PostOp
15,00 10,00
8,07
5,00
7,64 1,52
VAS
ODI
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0,00
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Figure 5. Comparison of preoperative and postoperative VAS and ODI values
ACCEPTED MANUSCRIPT ODI: Oswestry disability index VAS: Visual analog scale MD: Microdiscectomy YESS: Yeung Endoscopic Spine System
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TF: Transforaminal IL: Interlaminar FELD: Full-endoscopic lumbar discectomy
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MRI: Magnetic resonance imaging CT: Computed tomography
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PLL: Posterior longitudinal ligament
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CSF: Cerebrospinal fluid
