This document describes a study evaluating the efficacy of using a dynamic hip screw (DHS) drill under image intensifier guidance to ablate osteoid osteoma of the lower extremities in children and adolescents. Eighteen patients between ages 4-16 were treated with this minimally invasive technique, with 16 achieving initial success from one drilling. Complications included one tibial fracture and two skin abrasions. At follow-up, all patients were classified as having a good clinical response. The combination of intraoperative localization using image intensifier guidance and ablation with a DHS drill provided an efficient, safe, and curative procedure with minimal bone loss for treating osteoid osteoma.

1. Ablation of Osteoid Osteoma of Lower Extremity using Dynamic
Hip Screw Drill
Freih Odeh Abu Hassan1, F.R.C.S (Eng), F.R.C.S M.B.,BCh. Tarek Nayef Altamimi1, M.B.,BCh,J.P.Orth
الخلاصة
الاهداف : لتقييم فعالية الاسترشاد بجهاز الاشعه ذو الصوره الأكثر حده ومثقاب مفصل الورك الديناميكي ) 9مم( كطريقه
جراحيه دنيا في استئصال الورم العظمي شبيه بالعظم عن طريق الجلد في الاطراف السفليه عند الاطفال والبالغين.
مكان الدراسه : قسم جراحة العظام في مستشفى الجامعه الاردنيه - عمان
4 سنه ومتوسط اعمارهم - المواد والطرق : تم علاج 18 من الاطفال والبالغين ) 11 ذكور، 7 اناث( عمرهم يتراوح بين 16
) 18- 2006 . متوسط فترة المتابعه السريريه ) 35.37 ( شهر ) المدى 78 - 12.17 سنه في الفتره الواقعه مابين عام 1999
شهر. حالات في عظم القصبه. 414 حاله كانت في عظم الفخذ كل المرضى تمت معالجتهم من قبل الباحث الاول عن طريق
الجلد تحت المخدر العام باستخدام مثقاب مفصل الورك الديناميكي و جهاز الاشعه ذو الصوره الأكثر حده.
النتائج: دلت النتائج الاوليه شفاء 16 مريض )% 88.88 ( في الاسبوع الاول عن طريق الثقب مره واحده. احتاج مريضين
11.11% ( الثقب مره اخرى بعد اسبوعين نتيجة فشل المثقاب الاول أستهداف (
موطن نشوء الورم العظمي شبيه بالعظم . المضاعفات تضمنت كسر في عظم القصبه وحالتين تضمنت خدوش جلديه في
الساق نتيجة المثقاب. صنفت الاستجابه السريريه جيده في كل المرضى اعتمادا” على المتابعه الطويله والمتوسطه.
الاستنتاج : أستخدام جهاز الاشعه ذو الصوره الأكثر حده لتحديد موقع الورم العظمي شبيه بالعظم اثناء العمليه مع استخدام
مثقاب مفصل الورك الديناميكي أعطى طريقة شافيه أمينه وفعاله مع فقدان عظم قليل. يمكن استخدام هذه الطريقه كبديل
للتقنيات المعياريه لازالة الورم العظمي شبيه بالعظم. استخدام هذه الطريقه للقصبه يمكن ان يؤدي الى مضاعفات اكثر.
مفتاح الكلمات : الورم العظمي شبيه بالعظم.
Abstract
Objectives: Evaluate the efficacy of Image Intensifier- guidance percutaneous ablation of osteoid osteoma of lower
extremity in children and adolescents. using a dynamic hip-screw (DHS) drill pit (9- mm) as a minimally invasive
therapy.
Setting: Orthopaedic department at Jordan University Hospital –Amman.
Methods: The Study Started from November 1999 October 2006, Treating 18 children, (eleven males and seven females),
with a mean age of 12.17 years (range 4–16 years). The mean follow-up period was 35.37 months (range 18–78 months).
There were fourteen lesions in the femur and four in the tibia. All patients were treated percutaneously under Image
intensifier guidance by the first author under general anesthesia.
Results: Initial clinical success in the first week was achieved in 88.88% of children (16/18) from drilling once. Two
patients 11.11% needed redrilling two weeks later after failure of the first drilling to target the nidus. Complications
included one fractured tibia and two skin abrasions over the tibia. At long- and medium term follow-up, all patients were
classified to have good clinical response.
Conclusion: The combination of intraoperative localization of osteoid osteoma by image intensifier, using a dynamic
hip-screw (DHS) drill, resulted in an efficient, safe, and curative procedure with minimal bone loss. This method can be
used as an alternative to the standard techniques for removal of osteoid osteoma. Using the technique for the tibia may
be associated with higher incidence of complications
Keywords: Osteoid osteoma, Nidus, Image intensifier, Drilling, DHS drill.
1 Associate Professor of Orthopaedics and Paediatric Orthopaedic Surgery, Jordan University- Amman
JBMS Journal of the Bahrain Medical Society, July 2008 Vol 20, No. 3 101

2. Freih Odeh Abu Hassan, Tarek Nayef Altamimi
Introduction
Osteoid osteoma is a benign bone tumour consisting of
an osteoid nidus in a highly vascular connective tissue
stroma.1, 2 It accounts for approximately two-to-three per
cent of all primary bone neoplasms with a predilection for
the major long bones of patients younger than forty years.1,
2 These tumours are painful, and demonstrate characteristic
clinical picture and radiographic features. Clinical
diagnosis is made with the radiological appearance of a
small radiolucent area, known as the nidus, equal to or
less than 1.5 cms surrounded by a thick zone of sclerotic
bone which is smooth, convex, and homogeneously dense,
especially in the cortical bone.1 The traditional treatment
of osteoid osteoma consists of surgical en bloc excision.2, 3
but it has a high complication rate.4 Treatment varies from
conservative to surgical en bloc excision of the nidus .2, 3, 5
by percutaneous CT-guided excision, 6-8 destruction of the
nidus using radiofrequency thermocoagulation, 9-11 or laser
photocoagulation. 12, 13 These modalities have been shown
to have many advantages and fewer complications over
the traditional en block excision. Most minimal invasive
techniques require a special equipments, CT scan and
facilities for general anaesthesia for the removal of osteoid
osteoma. 2, 5, 7, 11, 13 These facilities are usually available
in special centers. We selected to use the commonly
available instruments. We have used a minimal invasive
percutaneous technique using a dynamic hip-screw (DHS)
drill (9 mm) successfully, with the aim of mechanical local
destruction of the nidus through a one centimetre incision
with minimal bone loss under direct visualization of the
image intensifier.
Materials and methods
From November 1999 to Octobar 2006, eighteen
consecutive children with osteoid osteoma were treated
with an image intensifier-guided percutaneous drilling
using a Dynamic Hip Screw drill pit (9-mm). There were
eleven males and seven females, with a mean age of 12.17
years (range 4–16 years), and the mean follow-up period
was 35.37 months (range 18–78 months).
(Table-1) All patients had typical clinical and radiographic
findings of osteoid osteoma. Pre-operative clinical
evaluation included detailed medical history, patients’
gender, age, location of the lesion, and thorough clinical
examination, pain severity, the response to aspirin or
anti-inflammatory drugs, the limitations of function, and
daily or recreational activities.All patients had severe
pain that usually worsened at night and had taken some
analgesics or narcotic injections and at least one course
of non-steroidal anti- inflammatory drugs for pain relief.
Pre-operative imaging evaluation included standard
radiographs, anterioposterior and lateral films.All patients
Figure-1: Plain radiograph of the hip showing well
visualized radiolucent nidus in the basal neck of the
femur with mild sclerosis
Table-1 Clinical characteristics of the patients
Patient
No.
Age
(years) Sex Site of the Lesion
Duration
of
symptoms
(months)
Follow-up
(months) Approach
1 10 F Femur neck 10 34 Lateral
2 13 M Femur neck 18 43 Lateral
3 10 F Femur neck 10 34 Lateral
4 14 F Femur neck 12 36 Lateral
5 16 M Femur neck 10 66 Lateral
6 16 M Femur neck 16 18 Lateral
7 12 M Femur neck 23 18 Medial
8 15 M Femur neck 13 20 Medial
9 13 F Trochanteric area 15 44 Lateral
10 15 M Trochanteric area 96 48 Lateral
11 5 M Subtrochanteric
area 18 20 Medial
12 4 F Proximal third
femur 6 22 Lateral
13 10 F Distal third
femur 18 42 Medial
14 15 F Distal third
femur 24 18 Lateral
15 11 F Proximal tibia 5 42 Anterior
16 14 M Proximal tibia 36 37 Anterior
17 14 M Shaft tibia 6 38 Medial
18 15 M Distal tibia 12 30 Anterior
102 JBMS Journal of the Bahrain Medical Society, July 2008 Vol 20, No. 3

3. Ablation of Osteoid Osteoma of Lower Extremity using Dynamic Hip Screw Drill
had computed axial tomography scans with positive
nidus, which allowed precise assessment of its size and
location. Six referred patients had bone Scintigraphy and
Magnetic Resonance Imaging (MRI) inspite all lesions
were very clear on a computed tomography (CT) scan.
Follow-up evaluation included clinical examination and a
questionnaire, and radiographic evaluation was conducted
postoperatively at regular intervals.Three cases required
postoperative CT-scans, two due to the persistence of their
initial symptoms and one for parents’ request. The delay
between referral to hospital and correct diagnosis varied
from 5 to 96 months (mean 19.75 months).The diagnosis
was clear on the plain radiographs by a well-visualized
nidus in thirteenpatients (Figure -1).Three cases of tibial
lesions needed a preoperative application of cross skin
mark under CT-scan guidance due to excessively dense
Figure-2A: Anterior posterior plain radiograph
demonstrating the insertion of the Kirschner wire inside
the nidus
bone. All cases had preoperative plan of the direction of
the guide wire after proper study of their plain radiograph
and CT-scan images for the exact location of the nidus.
Operative technique The Proce edures were performed by
first author with the patient on a radiolucent table under
general anaesthesia the affected part of the limb is examined
by a high- resolution image intensifier. Magnification and
adjustment of contrast are often required to see the nidus
clearly in both antero – posterior and lateral planes. After
cleaning and draping, a small (1 cm) skin incision was made
at the entry point guided by image intensifier and blunt
dissection was done with haemostat or mosquito.All cases
of neck femur lesions were approached from the lateral side
in the intertrochanteric region except two case from the
medial side, while in the other femoral and tibial lesions
we selected the appropriate approach.A 2.5 mms Kirschner
wire is introduced into the centre of the nidus crossing the
sclerotic bones by an air drill, under image-intensifier control
and viewed in two planes (Figure- 2A, B).
Figure-2B: Lateral plain radiograph demonstrating the
insertion of the kirschner wire inside the nidus.
Figure-3: Anterior posterior plain radiograph demonstrating
the insertion of the dynamic hip-screw (DHS) drill to
destruct the nidus.
In those cases with difficult visualization by image
intensifier the Kirschner wire is advanced perpendicular to
the transection of cross skin mark lines.A cannulated 9 mm
DHS drill pit is advanced automatically gradually along
the guide wire under the control of an image intensifier,
followed by drilling through the nidus without removing
a block of bone or curettage. (Figure-3) Two lesions, one
in the proximal tibia and one in the distal tibia, required
perforation of the anterior and posterior cortices of the
bone because the nidus was located in the posterior cortex.
At the end of the Proceedures, irrigation of the tract with
normal saline was performed and the wound was closed
with one stitch, followed by compressive sterile dressing.
JBMS Journal of the Bahrain Medical Society, July 2008 Vol 20, No. 3 103

4. Freih Odeh Abu Hassan, Tarek Nayef Altamimi
The patients were mobilized on protected, full-weight
bearing, on the first postoperative day with the help of
crutches for two weeks, and advised to avoid sports for a
minimum of six weeks.
Results
There were fourteen lesions in the femur and four in the
tibia. Lesion size was calculated from the CT scan from
the axial, sagittal and coronal cuts. The size was measured
from 5×5×3 mm to 14×13×8 mm. The average operating
time was sixteen minutes (range 7–21 minute). In the
morning following the operation a clinical evaluation was
performed for each patient to assess changes in his/her
preoperative symptoms. Patients were discharged home
on simple oral paracetamol analgesia for 5 days after
discharge. The average time in hospital after surgery was
1.3 days (range 1– 3 days). During follow-up, patients
were examined by the first author in the first week, second
week, and fourth week after the procedure, and then at
three months, six months and then annually, evaluating the
presence of pain or associated symptoms. A good initial
clinical response was achieved in 88.88 per cent of children
(16/18) in the first week postoperatively.
Figure-4: CT scan of the neck of femur showing nidus in
the posterior medial aspect of femoral neck that needed
twice drilling due to poor visualization.
There were two failures in the primary procedure, one
patient had a lesion situated within the posterior medial
cortex of the neck of the femur (Figure-4), and the other
in the posterior cortex of the proximal tibia, those two
cases had the same pattern of night pain after one week of
surgery, they required CT scan to identify the remaining
nidus, a repeat procedure through the original incision after
2 weeks of the original procedure and was successful in
both patients. Other complications included one case who
encountered a fractured tibia due to non compliant patient
who had a fall while playing football after two weeks of
surgery (Figure-5), which was treated conservatively by
the application of a cast for eight weeks. Two cases had
skin abrasions over the distal tibia caused by the drill,
which responded to local treatment. Rehabilitation was
rapid and uncomplicated and by six weeks patients had
returned to normal activities, including sport. At long- and
Figure-5: Lateral plain radiograph demonstrating the long
oblique fractured tibia with slight displacement and the
site of drilling hole in the midshaft of tibia .
medium term follow-up, all patients were classified as
good clinical response, thus 100% of the patients had a
good rating at the last evaluation.
Discussion
For many years, traditional surgical treatments have ranged
from local resection with a burr and curettage to wide
resection with bone grafting and metallic fixation, because
patients cannot tolerate the pain and wished to avoid the
long-term use of oral medications.2, 3, 5 Complete excision
of the nidus involves removal of the surrounding normal
bone. It is difficult to make an exact identification intra-operatively
because the nidus is usually too small, even
when CT, bone scanning, angiography, or fluoroscopic
guidance are used.2 Usually the nidus is well visualized
in good quality plain radiograph as happened in most
of our cases. The disadvantages of traditional surgical
excision are the need for wide resections disproportionate
to the small size of the lesion to ensure complete tumour
removal.2, 14 Therefore, patients may require longer period
of protected weight-bearing, may have pain at the bone
graft donor site, and may need to refrain from normal
activities for a prolonged interval.3, 5, 14 Surgical therapy is
successful in 88–100% of cases in the published series.15
Surgical treatment of osteoid osteoma should be used
only in locations that are inaccessible for a percutaneous
approach.2 Minimally invasive techniques have been
104 JBMS Journal of the Bahrain Medical Society, July 2008 Vol 20, No. 3

5. Ablation of Osteoid Osteoma of Lower Extremity using Dynamic Hip Screw Drill
developed to match the tissue damage to the small size of
the lesion. Different percutaneous techniques have been
described as alternative therapeutic options: percutaneous
resection under CT-guided radiofrequency ablation; and
laser photocoagulation.6, 8, 9, 10, 12 The advantages of these
minimally invasive techniques include the immediate
verification of complete nidus removal and rapid
relief of symptoms after nidus excision.7, 8, 11, 13 Many
current minimally invasive methods needs special tools,
instruments, anesthesia machine in the CT room and set up
system, which may not be present in each hospital.
Our technique a part from being minimally invasive, simple
and does not require special set up system, is performed by
general orthopaedist. This technique has been effective,
with a good clinical response in 88.23 per cent of cases
from the first drilling, and 100 per cent from the second
drilling. These results are comparable with other minimal
invasive methods. 5, 7, 8, 11, 13 There was one fracture in our
series due to non-compliance to strict non-sport activity
for six weeks postoperatively. The main disadvantage
of this technique is the lack of sufficient material for
pathological examination but this disadvantage should
not be viewed as a major insufficiency of the method,
especially as this is even observed after surgical excision
and other minimal invasive surgical procedures.3, 4, 8, 10, 12
On the other hand, histological confirmation with minimal-access
techniques is not crucial as appropriate diagnosis
can be made on clinical grounds reinforced by imaging
techniques.3, 9, 16,17 Other disadvantages is the limitation of
their use on the spine, and small-bone lesions owing to the
risk of a large drill hole, difficult localization of the nidus
under image intensifier and the risk of thermal injury to
neural tissue and this is applicable to other percutaneous
resection techniques.6-8 The patient needs to use crutches
as a protective precaution for the first two weeks only,
but this is not a real disadvantage as many other surgical
procedures need the same.18 The advantages to the patient
of a minimally invasive procedure, with small scars and
rapid mobilization, brief hospitalization, and immediate
protected, weight-bearing mobilization.We suggest that
our method is more applicable for the well-visualized
nidus through a plain radiograph by most orthopaedic
surgeons. The use of the radiolucent table and the high-resolution
image intensifier for anteroposterior and lateral
radiographs is familiar to all orthopaedic doctors and the
equipment of DHS reamer is widely available. The results
of this study confirm the long- and medium term efficacy
of this simple percutaneous technique of osteoid osteoma
in children and adolescents. We think that our technique
is a minimally invasive technique, simple, easy, safe, has
minimal bone loss, easily tolerated by the patient, with
shorter hospital stay, and a reliable procedure for well-visualized
osteoid osteoma of large bones of the lower
limbs if other expensive special tools are not available.
However using the technique for the tibia is associated
with more complications than with using it for the femoral
neck.
References
1. Dahlin DC, Unni KK. Bone tumours: general aspects
and data on 8542 cases, 4th edn. Thomas, Springfield
1987, pp 88–101.
2. Gangi A. Treatment of osteoid osteomas: review of available
therapeutic options: surgery, percutaneous resection,
percutaneous alcohol ablation or thermocoagulation. J
Radiol 1999; 80: 419–420.
3. Yildiz Y, Bayrakci K, Altay M, Saglik Y. Osteoid osteoma:
the results of surgical treatment. Int Orthop 2001; 25:
119–122.
4. Bisbinas I, Georgiannos D, Karanasos T. Wide surgical
excision for osteoid osteoma. Should it be the first-choice
treatment? Eur J Orthop Surg Traumatol 2004; 14: 151–
154
5. Kneisl JS, Simon MA. Medical management compared
with operative treatment for osteoid-osteoma. J Bone Joint
Surg (Am) 1992; 74: 179–185.
6. Assoun J, Jourlaud T, Chiavassu H, Bonnevialle P, Railhuc
N, Giron J,etal . Osteoid osteoma: CT-guided percutaneous
resection and follow-up in 38 patients. Radiology 1999;
212: 687–692.
7. Buhler M, Binkert C, Exner G. Osteoid osteoma: technique
of computed tomography-controlled percutaneous
resection using standard equipment available in most
orthopaedic operation rooms. Arch.Orthop.Trauma
Surg2001; 121: 458– 461.
8. Sierre S, Innocenti S, Lipsich J, Lanfranchi L, Questa
H, Moguillansky S Percutaneous treatment of osteoid
osteoma by CT-guided drilling resection in pediatric
patients Pediatr Radiol 2006; 36: 115–118.
9. Barei DP, Moreau G, Scarborough MT, Neel MD.
Percutaneous radiofrequency ablation of osteoid osteoma.
Clin Orthop Relat Res 2000; 373:115–124.
10. Lindner NJ, Ozaki T, Roed R, Gosheger G, Winkelmann
W, Wortler K. Percutaneous radiofrequency ablation in
osteoid osteoma. J Bone Joint Surg Br 2001; 83: 391–
396.
11. Torriani M, Rosenthal D. Percutaneous radiofrequency
treatment of osteoid osteoma. Pediatr Radiol 2002; 32:
615–618.
12. Gangi A, Dietemann JL, Gasser B, et al. Interstitial laser
photocoagulation of osteoid osteomas with use of CT-guidance.
Radiology 1997; 203:843–848.
13. Witt JD, Hall-Cruggs MA, Ripley P, Cobb P, Bown SG.
Interstitial laser photocoagulation for the treatment of
osteoid osteoma. J Bone Joint Surg (Br) 2000; 82: 1125–
1128
14. Campanacci M, Ruggieri P, Gasparini A, Ferrano
A, Campanacci L. Osteoid osteoma. Direct visual
identification and intralesional excision of the nidus with
minimal removal of bone. J Bone Joint Surg (Br) 1999;
81: 814–820
15. Cantwell CP, O’Byrne J, Eustace S. Current trends in
treatment of osteoid osteoma with an emphasis on
radiofrequency ablation. Eur Radiol 2004; 14:607–617.
16. Rosenthal DI, Hornicek FJ, Torriani M, Gebhardt MC,
Mankin HJ. Osteoid osteoma: percutaneous treatment with
radiofrequency energy. Radiology 2003; 229:171–175.
17. Woertler K, Vestring T, Boettner F, Winkelmann W, Heindel
W, Lindner N. Osteoid osteoma: CT-guided percutaneous
radiofrequency ablation and follow-up in 47 patients. J
Vasc Interv Radiol 2001; 12:717–722.
18. Sans N, Galy-Fourcade D, Assoun J, Jarlaud T, Chiavassa
H, Bonnevialle P, et al. Osteoid osteoma: CT-guided
percutaneous resection and follow-up in 38 patients.
Radiology 1999; 212: 687–692.
JBMS Journal of the Bahrain Medical Society, July 2008 Vol 20, No. 3 105