Unilateral Endoscopic Optic Nerve Decompression for Idiopathic Intracranial Hypertension: A Series of 10 Patients

Accepted Manuscript

Fully Endoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-termClinical Results of 163 Surgically Treated Patients

Altay Sencer , MD Ali Guven Yorukoglu , MD Mehmet Osman Akcakaya , MD YavuzAras , MD Aydin Aydoseli , MD Osman Boyali , MD Fahir Sencan , MD Pulat AkinSabanci , MD Cengiz Gomleksiz , MD Murat Imer , MD Talat Kiris , MD KemalHepgul , 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, FullyEndoscopic Interlaminar and Transforaminal Lumbar Discectomy: Short-term Clinical Results of 163Surgically Treated Patients, World Neurosurgery (2014), doi: 10.1016/j.wneu.2014.05.032.

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Results of 163 Surgically Treated Patients

Altay Sencer MD1, Ali Guven Yorukoglu MD2, Mehmet Osman Akcakaya MD3, Yavuz Aras

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

Unal MD1, Nail Izgi MD1, Ali Tuncay Canbolat MD1

1) Department of Neurosurgery, Istanbul School of Medicine, Istanbul University,

Istanbul/ Turkey

2) Department of Neurosurgery, Artvin State Hospital, Artvin/Turkey

3) Department of Neurosurgery, Taksim Training and Research Hospital,

Istanbul/Turkey

4) Department of Neurosurgery, Erzincan University Faculty of Medicine,

Erzincan/Turkey

Corresponding Author:

Mehmet Osman Akcakaya, MD

Taksim Egitim ve Arastırma Hastanesi, Nöroşirürji Klini ği

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

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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

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

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

(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.

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.

Conclusions: The results of our study show that fully endoscopic interlaminar or

transforaminal surgeries are safe and effective treatment modalities for lumbar disc

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

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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

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

through the last decade and is still the predominant surgical approach.

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,

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,

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

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,

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the management of lumbar disc herniations.

Various surgical techniques have been described; however, minimally invasive

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-

assisted techniques or fully endoscopic techniques.

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

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

efficacy of this approach.

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

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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

pain that was unresponsive to medical therapy. Only patients with cauda equina syndrome did

not undergo endoscopic surgery.

Magnetic resonance imaging (MRI) was performed in all cases. An additional

abdominal computed tomography (CT) scan was performed in order to visualize the

anatomical structures and to prevent retroperitoneal injuries related to the lateral access

techniques used by the TF approach for lumbar disc herniations above the L3-4 level.

Selection Criteria for Surgical Approach

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

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

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

the operating table to allow sterile biplanar fluoroscopic control. For both approaches, the skin

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

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

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

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

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useful than directly searching for the sequestering material. Free fluctuation of the PLL under

constant irrigation is a good indicator of an adequate decompression.

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

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

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

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.

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

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,

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

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

the operations.

Statistical Analysis

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

characteristics, using SPSS 16. A positive significance level was assumed at a probability of

less than 0.05.

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

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The follow-up time was 12 months. The distribution of the herniated disc levels and surgical

approaches are summarized in Table 1.

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

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

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.

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

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

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

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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

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.

Complications

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

transient, and complete recovery occurred, including the two patients who underwent two-

level discectomies. In only one case (0.6%), there was a permanent postoperative motor

deficit, resulting in “foot drop”.

Four patients experienced dysesthesia after the surgery (2.4%). All of the patients who

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

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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

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,

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

summarized in Table 3.

Clinical Outcomes

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

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

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

different diseases, especially in gastrointestinal, orthopedic, thoracic 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

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

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

skeptics.

Lumbar disc herniation is a major health problem, and successful surgical treatment of

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

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

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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

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

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

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

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

the aforementioned advantages which, although subjective, may be preferred both by patients

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

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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

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

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

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

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

improve endoscopic surgical skills.

Another serious complication of the lateral TF approach is visceral organ or vascular

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.

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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.

Additionally, inappropriate manipulation of the neural elements may result in transient or

permanent motor deficits. (49)

Good clinical results have been reported for endoscopic discectomies, even with

various TF and IL approaches, different patient selection criteria, and varying surgical

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

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

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

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

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residual herniation behind.

There were 15 complications (9%) in our series, with only one significant major

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

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

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–

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

multi-level disc herniations.

Dysaesthesias were encountered in four cases (2.4%), all of which were approached

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

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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

this technique. (20, 29, 49)

As our series demonstrates, attention must be paid, especially in the early stages of

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

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

recommend not attempting dural repair if a dural tear occurs.

Conclusions:

Currently, the goal of surgical treatment for lumbar disc herniations is optimal

decompression with minimal tissue trauma and complication. From this perspective, FELD is

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.

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1. Ahn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY. Percutaneous endoscopic lumbar

discectomy for recurrent disc herniation: surgical technique, outcome and prognostic factors

of 43 consecutive cases. Spine 29: 326-332, 2004

2. Andrews DW, Lavyne MH. Retrospective analysis of microsurgical and standart lumbar

discectomy. Spine 15: 329-335, 1990

3. Bover P, Srour R, Buchheit F, Krause D, Alberquerque M. [ Lumbar disc hernia. Excision

of hernia with or without complementary discectomy?] Neurochirurgie 40: 259-262, 1994

(Article in French)

4. Cansever T, Kabatas S, Civelek E, Kircelli A, Yılmaz C, Musluman M, Ofluoglu D, Caner

H. Transforaminal epidural steroid injection via a preganglionic approach for the treatment of

lumbar radicular pain. Turk Neurosurg 22(2): 183-188, 2012

5. Carragee EJ, Han MY, Suen PW, Kim D. Clinical outcomes after lumbar discectomy for

sciatica: the effects of fragment type and anular competence. J Bone Joint Surg Am 85: 102-

108, 2003

6. Carragee EJ, Spinnikie AO, Alamin TF, Paraqioudakis S. A prospective controlled study of

limited versus subtotal posterior discectomy: short term outcomes in patients with herniated

lumbar intervertebral discs and large posterior anular defect. Spine 31: 653-657, 2006

7. Caspar W, Iwa H. A microsurgical operation for lumbar disc herniations. Neurol Surg 6:

657-662, 1979

8. Chiu JC. Evolving transforaminal endoscopic microdecompression for herniated lumbar

discs and spinal stenosis. Surg Tech Int 13. 276-286, 2004

9. Dandy WE. Loose cartilage from intervertebral disc simulating tumor of the spinal cord.

Arch Surg 19: 660-672, 1929

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ACCEPTED MANUSCRIPT10. 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

12. Fairbank JC, Couper J, Davies JB, O’ Brein JP. The Oswestry low back pain

questionnaire. Physiotherapy 66: 271-273, 1980

13. Ferrer E, Garcia-Bach M, Lopez L, Isamat F. Lumbar microdiscectomy: Analysis of 100

consecutive patients. Acta Neurochir Suppl (Wien) 43: 39-43, 1988

14. Foley KT, Smith MM, Rampersaud YR. Microendoscopic approach to far-lateral lumbar

disc herniation. Neurosurg Focus 7(5): e5, 1999

15. Forst R, Hausmann B. Nucleoplasty- a new examination technique. Arch Orthop Trauma

Surg 101: 219-221, 1983

16. Hermantin FU, Peters T, Quartarato IA, Kambin P. A prospective, randomized study

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.

Clin Ortop Relat Res 238: 9-23, 1989

18. Hirabayashi S, Kumano K, Ogawa Y, Aota Y, Maehiro S. Microdiscectomy and second

operation for lumbar disc herniation. Spine 18: 2206-2211, 1993

19. Hoogland T, Schubert M, Miklitz B, Ramirez A. Transforaminal posterolateral

endoscopic discectomy with or without the combination of a low-dose Chymopapain: a

prospective randomized study in 280 consecutive cases. Spine 24: 890-897, 2006

20. Kafadar A, Kahraman S, Akboru M. Percutaneous endoscopic transforaminal lumbar

discectomy: A critical appraisal. Minim Invas Neurosurg 49: 74-79, 2006

MANUSCRIP

T

ACCEPTED

ACCEPTED MANUSCRIPT21. Kambin P, Gellman H. Percutaneous lateral discectomy of the lumbar spine: a preliminary

report. Clin Orthop 174: 127-132, 1983

22. Kambin P, Sampson S. Posterolateral suction-excision of herniated lumbar intervertebral

discs: report of interim result. Clin Orthop 207: 37-43, 1986

23. Kambin P. Arthroscopic microdiscectomy. Arthroscopy 8: 287-295, 1992

24. Kambin P, Casey K, O’Brein E, Zhou L. Transforaminal arthroscopic decompression of

the lateral recess stenosis. J Neurosurg 84: 462-467, 1996

25. Kambin P, O’Brein E, Zhou L, Schaffer JL. Arthroscopic microdiscectomy and selective

fragmentectomy. Clin Orthop 347: 150-167, 1998

26. Kim JM, Lee SH, Ahn Y, Yoon DH, Lee CD, Lim ST. Recurrence after successful

percutaneous endoscopic lumbar discectomy. Minim Invas Neurosurg 50: 82-85, 2007

27. Kim WJ, Lim ST, Lee SH. Pyogenic psoas abscess and secondary spondylodiscitis as a

rare complication of percutaneous endoscopic lumbar discectomy: a case report. Joint

Diseases and Related Surgery 16: 163-166, 2005

28. Kotilainen E, Valtonen S. Clinical instability of the lumbar spine after microdiscectomy.

Acta Neurochir (Wien) 125: 120-126, 1993

29. Kuonsongtum V, Paiboonsirijit S, Kesornak W, Chaiyosboorana V, Rukskul P,

Chumnanvej S, Ruetten S. Result of full endoscopic uniportal lumbar discectomy: preliminary

report. J Med Assoc Thai 6: 776-780, 2009

30. Lee DY, Ahn Y, Lee SH. Percutaneous endoscopic lumbar discectomy for adoslescent

lumbar disc herniation: surgical outcomes in 46 consecutive patients. Mt Sinai J Med 73: 864-

870, 2006

31. Lee DY, Lee SH. Learning curve for percutaneous endoscopic lumbar discectomy. Neurol

Med Chir 48: 383-389, 2008

MANUSCRIP

T

ACCEPTED

ACCEPTED MANUSCRIPT32. Lee SH, Kang BU, Ahn Y, Choi G, Choi YG, Ahn KU, Shin SW, Kang HY. Operative

failure of percutaneous endoscopic lumbar discectomy: a radiological analysis of 55 cases.

Spine 31: E285-E290, 2006

33. Mayer HM, Brock M, Berlien HP, Weber B. Percutaneous endoscopic laser discectomy

(PELD). A new surgical technique for non-sequestrated lumbar discs. Acta Neurochir Suppl

(Wien) 54: 53-58, 1992

34. Mixter WJ, Barr JS. Rupture of intervertebral disc with involvement of the spinal canal. N

Eng J Med 211: 210-215, 1934

35. Nellenstejn J, Ostelo R, Bartels R, Peul W, van Royen B, van Tulder M. Transforaminal

endoscopic surgery for symptomatic lumbar disc herniations: a systematic review of the

literature. Eur Spine J 19: 181-204, 2010

36. Oertel JMK, Mondorf Y, Gaab MR. A new endoscopic spine system: the first results with

“Easy GO”. Acta Neurochir (Wien) 151: 1027-1033, 2009

37. Righesso O, Falavigna A, Avanzi O. Comprasion of open discectomy with

microendoscopic discectomy in lumbar disc herniations: results of a randomized controlled

trial. Neurosurgery 61: 545-549, 2007

38. Ruetten S. The full-endoscopic interlaminar approach for lumbar disc herniations. In:

Mayer HM (ed), Minimally Invasive Spine Surgery. Berlin: Springer. 2005, pp: 346-355

39. Ruetten S, Komp M, Godolias G. An extreme lateral access for the surgery of lumbar disc

herniations inside the spinal canal using the full-endoscopic uniportal transforaminal

approach: Technique and prospective results of 463 patients. Spine 30: 2570-2578, 2005

40. Ruetten S, Komp M, Godolias G. A new full-endoscopic technique for the interlaminar

operation of lumbar disc herniations using 6-mm endoscope; Prospective 2-year results of 331

patients. Minim Invas Neurosurg 2: 80-87, 2006

MANUSCRIP

T

ACCEPTED

ACCEPTED MANUSCRIPT41. Ruetten S, Komp M, Merk H, Godolias G. Use of newly developed instruments and

endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar

approach. J Neurosurg Spine 6: 521-530, 2007

42. Ruetten S, Komp M, Merk H, Godolias G. Full-endoscopic interlaminar and

transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective

randomized, controlled study. Spine 33: 931-939, 2008

43. Sasani M, Ozer AF, Oktenoglu T, Canbulat N, Sarioglu AC. Percutaneous endoscopic

discectomy for far lateral lumbar disc herniations: prospective study and outcome of 66

patients. Minim Invas Neurosurg 50(2): 91-97, 2007

44. Screiber A, Suezawa Y, Leu H. Does percutaneous nucleotomy with discoscopy replace

conventional discectomy? Eight years of experience and results in treatment of herniated

lumbar disc. Clin Orthop Relat Res 238: 35-42, 1989

45. Schreiber A, Leu H. Percutaneous nucleotomy: technique with discoscopy. Orthopedics

14: 439-444, 1991

46. Stambough JL. Lumbar disc herniation: an analysis of 175 surgically treated cases. J

Spinal Disord 10: 488-492, 1997

47. Tsou PM, Yeung AT. Transforaminal endoscopic decompression for radiculopathy

secondary to intracanal noncontained lumbar disc herniations: outcome and technique. Spine J

2: 41-48, 2002

48. Valls J, Ottolenghi CE, Schajowicz F. Aspiration biopsy in diagnosis of lesions of

vertebral bodies. J Am Med Assoc 136(6): 376-382, 1948

49. Wang B, Lu G, Patel AA, Ren P, Cheng I. An evaluation of the learning curve for a

complex surgical technique: the full endoscopic interlaminar approach for lumbar disc

herniations. Spine J 11: 122-130, 2011

MANUSCRIP

T

ACCEPTED

ACCEPTED MANUSCRIPT50. Wenger M, Mariani L, Kalbarczyk A, Groger U. Long-term outcome of 104 patients after

lumbar sequestrectomy according to Williams. Neurosurgery 49: 329-334, 2001

51. Williams RW. Microlumbar discectomy. A 12-year statisticaal review. Spine 11: 851-852,

1986

52. Yasargil MG. Microsurgical operation for herniated disc. In: Wullenweber R, Brock M,

Hamer J, Klinger M, Spoerri O (eds), Advances in Neurosurgery. Berlin: Springer-Verlag,

1977: pp 81-82

53. Yeung AT. Minimally invasive disc surgery with the Yeung Endoscopic Spine System

(YESS). Surg Tech Int 8: 1-11, 1999

54. Yeung AT. The evolution of percutaneous spinal endoscopy and discectomy: state of the

art. Mt Sinai J Med 67: 327-332, 2000

55. Yeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar disc herniation:

Surgical techniques, outcome and complications in 307 consecutive cases. Spine 27: 722-773,

2002

56. Yeung AT, Yeung CA. Advances in endoscopic disc and spine surgery: foraminal

approach. Surg Tech Int 11. 255-263, 2003

57. Yorimitsu E, Chiba K, Toyama Y, Hirabayashi K. Long-term outcomes of Standard

discectomy for lumbar disc herniation. Spine 26: 652-657, 2001

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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

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

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.

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.

Figure 5: The bar graph shows the differences between pre- and postoperative ODI and VAS

scores.

Acknowledgments:

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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Table 1

Levels Transforaminal Interlaminar Total

L1 – L2 3 - 3

L2 – L3 7 3 10

L3 – L4 14 3 17

L4 – L5 44 49 93

L5 – S1 3 49 52

Total 71 104 175

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Table 2

Ptn

IDEtiology Levels

1st

Op

Time in

btw

2nd

OpOutcome

1 Recurrence L5 - S1 TF 3 months MD Better

2 Residual L4 - L5 TF 1 month TF Better

3 Recurrence L4 - L5 IL 2 months IL Same

4 Recurrence L5 - S1 IL 1 week IL Better

5 Recurrence L5 - S1 IL 1 month IL Same

6 Recurrence L3 - L4 TF 2 months TF Better

7 Recurrence L5 - S1 IL 2 weeks MD Better

8 Residual L4 - L5 TF 1 week TF Same

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Table 3. Complications

Complication 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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8,07

37,04

1,52

7,64

0,00

5,00

10,00

15,00

20,00

25,00

30,00

35,00

40,00

VAS ODI

PreOp

PostOp

Figure 5. Comparison of preoperative and postoperative VAS and ODI values

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VAS: Visual analog scale

MD: Microdiscectomy

YESS: Yeung Endoscopic Spine System

TF: Transforaminal

IL: Interlaminar

FELD: Full-endoscopic lumbar discectomy

MRI: Magnetic resonance imaging

CT: Computed tomography

PLL: Posterior longitudinal ligament

CSF: Cerebrospinal fluid