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July2014 Vol.51 Issue:      3 (Supp.) Table of Contents
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Clinical Outcome of Percutaneous Fixation in Symptomatic Lumbosacral Spondylolisthesis

Mahmoud I. Abdel-Ghany1, Mohammed A. Yehia1, Ahmed I. Abdel-Salam1,

Abdel-Hamid Abdel-Aziz1, Mohammed Al-Wardany2

Departments of Orthopedics1, Al-Azhar University; Neurosurgery2, Ain Shams University; Egypt


Background: Minimally invasive techniques in spinal surgery are increasing popularity as it reducing length of stay, morbidity risk, post-operative analgesia and early return to work. Objective: A prospective study to evaluate the clinical outcome of percutaneous fixation for disabling low back pain associated with lumbosacral GI spondylolisthesis. Methods: Twenty patients with 1st degree lumbar spondylolisthesis underwent percutaneous fixation after failure of at least 6 months of conservative treatment. All patients with neurological compromise and requiring decompression or had previous spine surgery were excluded. There were 16 males (80%) and four female (20%). Patient’s age ranged from 30 to 42 years old with average age 37 years old. Clinical outcome was evaluated by Japanese Orthopedic Association Score (JAOS). Operative time, blood loss, and postoperative pain were also recorded. Results: Average follow up periods were 15.5 months. According to JOAS mean preoperative score was 18, which are improved to mean 27.85. Overall results were excellent mean improvement rate were 89.76%. Mean operative time 96 minutes; mean blood loss was 100 mL. Postoperative X-Ray has proper screws position. The complications occurred in two cases (10%) and dealt with them accordingly. Conclusion: Percutaneous fixation for management of symptomatic 1st lumbosacral spondylolisthesis allows for safe and efficient minimally invasive procedure had good clinical results. Further prospective studies with long-term follow-up results are required to assess the definitive merits of percutaneous instrumentation of the lumbar spine. [Egypt J Neurol Psychiat Neurosurg.  2014; 51(3): 287-293]

Key Words:  Percutaneous, Spondylolisthesis, Minimally invasive surgery.

Correspondence to Mahmoud I. Abdel-Ghany, Orthopedics Department, Al-Azhar University, Egypt. Tel.: +201005196727    Email:



Pedicle screws have superior biomechanical as well as clinical data when compared to other methods of instrumentation1,2 .Several authors have been reported that the open posterior approach and instrumentation for the lumbosacral spine possibly adds relevant damage to the dorsal musculature and as a consequence continuous impairments can remains.3-5

Irrespective of the exact method of arthrodesis, conventionally open lumbar surgery performed via a posterior approach is associated with significant soft tissue morbidity that can adversely affect patient outcomes.6,7

Currently, there has been increased awareness of the need to preserve stability and minimize destruction to tissues not directly involved in the pathological process. Several authors have described their experiences with minimally invasive surgery for different pathology and reported its efficacy and safety. However, these techniques are technically demanding even though their results have been reported to be favorable.8-10

Aim of work: To evaluate an alternative minimal invasive technique for the treatment of 1st degree lumbosacral spondylolisthesis regarding the technique and to determine its clinical outcome.




From March 2009 to May 2010 twenty patients diagnosed to have 1st degree spondylolisthesis of the lumbosacral spine resulting in axial back pain and claudication, without other radicular symptoms underwent percutaneous pedicle screw fixation (PPSF) after failure of at least 6 months of conservative treatment. Patients who proved had neurological deficits and requiring decompression or had previous spine surgery were excluded from the study. There were 16 males (80%) and four females (20%). Patients’ ages ranged from 30 to 42 years old with average 37 years old.

The clinical status of all patients had been evaluated and so the clinical outcome was assessed by JOAS.11 JOAS were recorded for all patients before surgery and after surgery regularly to the last follow up visit. Calculation of Improvement rate by using the formula included in the score by calculating the total score before surgery and the last follow up score. Radiological evaluation by plain X-ray AP, lateral and oblique films (right and left oblique) on the lumbosacral spine region and dynamic views (lateral standing flexion-extension) to evaluate the stability of the affected segment. Magnetic Resonance Imaging (MRI) of the lumbosacral spine was also performed for all patients to confirm that there is no need for decompression of the neural elements. Intra-operative blood loss, time of surgery, intra-operative blood loss, and were recorded.

The main complaint of patients was low back pain with an average duration of complaint 1.8 years. The duration of complaint was less than 3 years in 13 patients (65%) and less than 5 years in 7 patients (35%). Fifteen patients (75%) had continuous severe back pain that led to reduction of their activities of daily living. Five patients (25%) had frequent mild back pain or occasional severe pain that also that led to reduction of their daily living activities. Six patients (30%) had low back pain associated with unilateral leg pain.

The level of fusion for all patients were L5-S1 and grade of slipping is G1 on Myerding’s Scale with few mm. displacement which usually does not appears until dynamic films were obtained. 

All patient in this study treated surgically by minimal invasive procedure using percutaneous pedicle screws fixation with Sextant rod system (Medtronic SofamorDanek, USA®) in all cases. After induction of general anesthesia, patients were positioned prone on a radiolucent frame. Fluoroscopic image was used directly after positioning to identify and draw crossed lines over the skin at the pedicle site before scrubbing (Figure 1). Bone marrow (BM) injection needle with sharp trocar (Islam Needle Manufactured by Down®) were used initially to access the pedicle with fluoroscopic confirmation (AP and lateral view) (Figure 2). Guide wire inserted through the BM needle in the center of the pedicle and the needle is removed and fluoroscopic control. Cannulated screws with poly-axial screw heads that connect to extension sleeves were inserted. Pre-contoured suitable length rod were inserted and inter-connected to the pedicle screw heads through special Assembly of the system (Figure 3). The accuracy of pedicle screw position was evaluated by direct postoperative plain X-ray AP and Lateral views (Figure 4).

                The average operative time was 96 minutes (ranged 60-140 minutes). The average estimated blood loss was 100mL (ranged 75-150 mL). Postoperatively all patients were advised to use lumbosacral support orthosis when out of bed for 12 weeks. In all pa­tients, sitting and walking were allowed at the same day of surgery.

All patients were discharged from hospital at 2-6 days postoperatively. The mean postoperative stay was 3 days. For manual worker patients light work was allowed after 8 weeks while active work was allowed after 3 months. For heavy strain worker patients work activities modification was advised where returning to their high normal level work activity was not allowed for at least 6 months after surgery.


Statistical Analysis

Statistical analysis of the results including mean val­ues and standard deviations was performed using SPSS version16, to analyze all clinical data pre and postoperatively according to JOAS. We also used Chi-Square test and Simple T-test to compare pre and post-operative data. Differences were considered statistically significant at p<0.05.




All patients were followed up and evaluated both clinically and radiologically postoperatively with a mean follow-up period of 15.5 months (ranged 6-26).

According to the JOAS results were recorded preoperatively and at the final follow-up evaluation. All patients showed improvement in their main complaint “back pain”. According to JOASall patients have no back pain has significant difference, as score improved from 0-2 to 3 (no pain). Leg pain had been improved in all patients as their preoperative JOAS for leg pain ranged from 0-2 and changed to 3 (normal) in all patients. Gait also has significantly improved from 0-1 in 6 patients (30%) out of 20 improved to 3 (normal). For Activity Day Living according to JOAS  had been significantly improved from 5-8 preoperatively to 14 (no restriction of ADL)

According to the formula of the JOAS improvement rates in all patients were calculated and recorded. Total improvement rate for all patients was classified into Excellent, Good, Fair and Poor. All patients improvement rate had Mean 98.8±9.2 (ranged from 76.9 - 100) and were classified as excellent improvement rate. In addition, all other parameters listed in the JAOS showed statistically significant difference improvement (P-value = 0.000 - 0.017) postoperatively (Table 1).



Figure 1. (A) Identification of pedicle level with wire before inserting needle.

(B) Skin drawing and incision over the pedicles.




Figure 2. Fluoroscopy image AP and lateral shows access of the pedicle with Islam® Bone marrow needle.




Figure 3. (A) Assembly for rode insertion through separate incision after placement of screws,

(B) Assembly after insertion of rode, (C) Fluoroscopic image to confirm proper placement of the rodes.




Figure 4. (A) pre-operative X-ray (Antero-Posterior and Lateral), (B) MRI (T2W) sagittal and axial images, (C) Direct post operative plain X-ray (Antero-Posterior and Lateral views), (D) Six months F-up Plain X-ray (Antero-Posterior and Lateral) shows trabecular cross through the pars.

Table 1. Comparison between individual Item of JAOS.


JAOS  Item



Lower Back Pain


0.30± 0.47




Leg Pain / Tingling












Turn over while lying


















Leaning forward






Sitting about 1 hour






Lifting or holding Objects












JOAS Japanese Orthopedic Association Score.

*Significant at P<0.05 **Significant at P<0.01


Immediate postoperative plain X-ray was to confirm proper position of screws with no invasion of the wall of the pedicle (Figure 4). At a minimum of 12 months fol­low-up, all cases appeared to have solid fusions as judged by the presence of a trabecular bony bridge at the last follow up.

There was no complications comparative to open surgery for wound site infection, postoperative pain and increasing needs for analgesia. However, we noted one patient (5%) with postoperative left Buttock pain. It was transient and improved conservatively after 3 weeks. Another patient (5%) had persistent pain during postoperative follow up evaluation at 6 months. The patient was re-operated where graft was applied from small wounds over the pars. Five months later there was pars union detected radiologically and the pain improved completely.




Traditionally, a posterior spinal fusion with instrumentation requires a moderate amount of muscle dissection for placement of the bone graft. This muscle dissection, accompanied by denervation of facet capsules and weakening of other supportive structures, gives rise to the concept of “fusion disease” and the concomitant lingering effect of less than optimal functional recovery.12

In order to limit disadvantages related to the conventional approach, some minimally invasive techniques have been developed in the past 10 years to treat degenerative diseases. The posterior minimally invasive approach was initially utilized in cases requiring a simple decompression such as discectomy or foraminotomy. Later, the continuous evolution of this technique and the experience acquired allow a true pedicle screw fixation and fusion for a minimally invasive approach.13

In the past few years, many authors have reported the advantages of the mini-invasive posterior lumbar approach versus the conventional open procedures such as the reduction of intra-operative blood loss, less damage to soft tissues, relief of postoperative pain, early mobilization of the patient, shorter hospital stay, and a rapid return to an active social and working life.5,10,14,15

The indication of surgery in this study was 1st degree isthmic spondylolisthesis of the lumbosacral spine not responding to conservative treatment. As mentioned before, all patients were neurologically free. In our study there were no cases was converted into open surgery due to tech­nical difficulty.

We used Sextant rod system. In the other studies, the majority if not the whole used the Sextant rod system. The advantage of that system was easy in reduction of spondylolisthesis could be achieved with the aid of extension sleeves in rod system and the application of rods was on ease; also the rods were flexible and easily pre-contoured.

The main complaint was back pain in 70% and all cases were neurologically free. Leg and claudication pain, which was present in 30%, can be explained by the transient entrapment of nerve root at this level from the dynamic instability and this was the same explanation of Sahoo16 in his series. He found that two cases out of six cases of 1st and 2nd degree spondylolisthesis had leg and claudication pain.

The average operative time was 96 minutes (ranged from 60 to 140 minutes) that is compared to 90-220 minutes in the study of Foley and colleagues.17 The longer time duration (140 minutes) was during the early cases, we attributed this to our initial experience and learning curve.

Mayer and colleagues18demonstrated long-term radiographic atrophy of the operated muscle segment on CT scanning after cases requiring extensive posterior surgical exposure. Recent studies analyzed the amount of muscle damage, via measurements of creatine kinase (CK), which occurs with various types of spine surgery. Open lumbar fusions had a significantly higher amount of CK (muscle damage) in comparison to other minimally invasive procedures.19

Minimally invasive techniques are used where the percutaneous system acts as a tension band device so it reduces the iatrogenic damage to the paraspinous muscles and virtually no need for blood transfusion.20 We agree with the previous studies that patients who underwent percutaneous pedicle screw-fixation procedures did not require blood transfusion, where the amount of blood loss was mild. The mean estimated blood loss was 100 mL (ranged 75- 150 mL). We also agree with Foley and Gupta20 for the concept of the tension band device mechanism, which is dynamic-fixation device causing bony union with motion, so we did not use bone graft as we expect union of the lysis part by dynamic fixation (tension band)

The patients recovered quickly from the surgical procedure. As regard hospital stay, Foley and Gupta20 stated that fifty percent of their patients were discharged on the 1st and 2nd day postoperatively, while the remaining patients were discharged on the 3rd day with short period of rehabilitation and return to their usual work. In this study, the mean postoperative hospital stay was 3 days (range 2-6 days postoperatively) as the majority of our patients were referred from areas faraway from our city, therefore, we preferred them to stay in the hospital until they can withstand the difficulty of traveling, in addition to have grantee for good rehabilitation before discharge.

All cases were clinically assessed pre and postoperatively using the JOAS and the improvement rate was calculated accordingly. Our results shows mean Improvement Rate was 89.76% at the final assessment which has significant difference (p=0.017). These rates are better than those reported in the study of Kimura21for open pedicle screw fixation of the lumbosacral spondylolisthesis (81.8%) and Suk22 (84.4%). Thus minimal invasive procedure offers better improvement outcome rates.

Foley and Gupta20 reported that successful percutaneous pedicle screw fixation in which the rod-insertion device was used in twelve patients. In addition, paraspinous tissue trauma is minimized without compromising the quality of spinal fixation, that was reported in 10 patients and osseous nonunion of a prior interbody fusion was present in two patients and one patient had hardware revision.

We have only one patient had osseous nonunion in the postoperative follow up evaluation at 6 months. The patient was re-operated where graft was applied. All other cases appeared to have solid fusions as judged by the presence of a trabecular bony bridge.

In our series, only one case (5%) had postoperative left buttock pain, which was transient, and patient improved spontaneously. One patient (5%) also had back pain on the 6thmonth postoperatively where the patient was re-operated up bone graft was applied and the pedicular screws were adjusted.



Percutaneous pedicle screw fixation for management of symptomatic 1st lumbosacral spondylolisthesis allows for safe and efficient minimally invasive procedure with satisfactory clinical results. It reduces the size of the midline skin incision as well as the risks for iatrogenic muscle injury usually accompanying the traditional open procedures. Further prospective studies with long-term follow-up results are required to assess the definitive merits of percutaneous instrumentation of the lumbar spine. For while we have to keep the implants but after removal of these implants further evaluation will confirm the stability after this procedure. Clinical outcome is encouraging; however, the results after long-term follow up will decide the full success of the technique.


[Disclosure: Authors report no conflict of interest]




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3.          Weber BR, Grob D, Dvorak J, Muntener M. Posterior surgical approach to the lumbar spine and its effect on the multifidus muscle. Spine. 1997; 22:1765-72.

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6.          Sihvonen T, Herno A L, Paljärvi O, Airaksinen J, Partanen, Tapaninaho A. Local denervation atrophy of paraspinal muscles in postoperative failed back syndrome. Spine.1993; 5:575-81.

7.          Styf JR, Willén J. The effects of external compression by three different retractors on pressure in the erector spine muscles during and after posterior lumbar spine surgery in humans. Spine. 1998; 3:354-8.

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الملخص العربي


النتائج الإكلينيكية لتركيب المسامير بالفقرات القطنية عبر الجلد فى حالات تزحلق الفقرات القطنية


تعد هذه الدراسة واحدة من الدراسات والأبحاث القليلة التى تتناول موضوع تركيب المسامير بالفقرات القطنية عبر الجلد ودون جراحة فى حالات تزحلق الفقرات القطنية والتى تسبب الأم شديدة بأسفل الظهر وهذا الإجراء من شانه ان يجنب المريض عددا من المضاعفات التى قد تصاحب الجراحة التقليدية لتركيب هذه المسامير هذا بالإضافة إلى أن هذا الإجراء يؤدى إلى تقليل ملحوظ ومؤثر فى مدة إقامة المريض بالمستشفى وكمية المسكنات بعد العملية وسرعة عودة المريض إلى عمله

وقد أجريت هذه الدراسة على عدد عشرون مريضا 16 من الذكور و4 من الإناث وقد كان جميع المرضى قد تلقوا علاجا تحفظيا لمدة ستة أشهر على الأقل وقد تم استبعاد جميع المرضى الذين يعانون من إصابة عصبية أو يحتاجون إلى استئصال شرائح عظمية من الظهر او قد اجري لهم جراحة بالفقرات القطنية قبل هذا الإجراء

وتتراوح أعمار المرضى الذين أجرى عليهم هذا البحث من 30-42 عاما بمتوسط للعمر يبلغ 37 عاما وقد استخدمت مقاييس عالمية لحاسب الألم ونتائج الإجراء قبل وبعد الإجراء هذا بالإضافة الى حساب (وقت الإجراء -فاقد الدم -الألم ما بعد الإجراء) وذلك لتقييم الدقيق ولمدى فاعلية هذا الإجراء.

وتضمن هذا البحث مدة للمتابعة ما بين (6- 26) شهرا بمتوسط خمسة عشر شهراً و 15 يوم للمرضى وقد كانت النتائج لهذا الإجراء تبعا للمقاييس العالمية كالاتي: ممتاز لمعظم المرضى، ووقت الإجراء يتراوح ما بين (60-140) دقيقة بمتوسط 96 دقيقة والدم المفقود كان ما بين (75-150 مل) بمتوسط 100 مل للإجراء الواحد وقد أجرى لجميع المرضى بعد الإجراء أشعة اكس لتقييم وضع المسامير بالفقرات القطينة وقد كانت نسبة المضاعفات لا تتعدل 10% من الحالات وتم التعامل معها.

ومما سبق يمكن القول بان تركيب المسامير بالفقرات القطنية عبر الجلد فى حالات تزحلق الفقرات القطنية والمصاحبة لها آلام شديد بأسفل الظهر يعد هذا الإجراء تبعا لهذه الدراسة أجراء امناً وناجحا ويطرح بشدة كبديل للجراحة التقليدية مع التوجيه بمزيد من الأبحاث لهذا الإجراء لتصل إلى التقييم الأمثل لهذه الجراحات بالفقرات القطنية فى حالات تزحلق الفقرات القطنية

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