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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_3 | Pages 102 - 102
23 Feb 2023
Campbell T Hill L Wong H Dow D Stevenson O Tay M Munro JT Young S Monk AP
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Contemporary indications for unicompartmental knee replacement (UKR) include bone on bone radiographic changes in the medial compartment with relatively preserved lateral and patellofemoral compartments. The role of MRI in identifying candidates for UKR is commonplace. The aim of this study was to assess the relationship between radiographic and MRI pre-operative grade and outcome following UKR.

A retrospective analysis of medial UKR patients from 2017 to 2021. Inclusion criteria were medial UKR for osteoarthritis with pre-operative and post-operative Oxford Knee Scores (OKS), pre-operative radiographs and MRI.

89 patients were included. Whilst all patients had grade 4 ICRS scores on MRI, 36/89 patients had grade 3 KL radiographic scores in the medial compartment, 50/89 had grade 4 KL scores on the medial compartment. Grade 3 KL with grade 4 IRCS medial compartment patients had a mean OKS change of 17.22 (Sd 9.190) meanwhile Grade 4 KL had a mean change of 17.54 (SD 9.001), with no statistical difference in the OKS change score following UKR between these two groups (p=0.873). Medial bone oedema was present in all but one patient. Whilst lateral compartment MRI ICRS scores ranged from 1 to 4 there was no association with MRI score of the lateral compartment and subsequent change in oxford score (P value 0.458). Patellofemoral Compartment (PFC) MRI ICRS ranged from 0 to 4. There was no association between PFC ICRS score and subsequent change in oxford knee score (P value .276)

Radiographs may under report severity of some medial sided knee osteoarthritis. We conclude that in patients with grade 3 KL score that would normally not be considered for UKR, pre-operative MRI might identify grade 4 ICRS scores and this subset of patients have equivalent outcomes to patients with radiographic Grade 4 KL medial compartment osteoarthritis.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 31 - 31
1 Dec 2016
Younger A Penner M Glazebrook M Goplen G Daniels T Veljkovic A Lalonde K Wing K Dryden P Wong H
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Reoperations may be a better way of tracking adverse outcomes than complications. Repeat surgery causes cost to the system, and often indicate failure of the primary procedure resulting in the patient not achieving the expected improvement in pain and function. Understanding the cause of repeat surgery at the primary site may result in design improvements to implants or improvements to fusion techniques resulting in better outcomes in the future. The COFAS group have designed a reoperation classification system. The purpose of this study was to outline the inter and intra observer reliability of this classification scheme.

To verify the inter- and intra-observer reliability of this new coding system, six fellow ship trained practicing foot and ankle Orthopaedic surgeons were asked to classify 62 repeat surgeries from a single surgeons practice. The six surgeons read the operation reports in random order, and reread the reports 2 weeks later in a different order. Reliability was determined using intraclass correlation coefficients (ICC) and proportions of agreement. The agreement between pairs of readings (915 for inter observer for the first and second read – 61 readings with 15 comparisons, observer 1 with observer 2, observer 1 with observer 3, etc) was determined by seeing how often each observer agreed. This was repeated for the 366 ratings for intra observer readings (61 times 6).

The inter-observer reliability on the first read had a mean intra-class correlation coefficient (ICC) of 0.89. The range for the 15 comparisons was 0.81 to 1.0. Amongst all 1830 paired codings between two observers, 1605 (88%) were in agreement. Across the 61 cases, 45 (74%) were given the same code by all six observers. However, the difference when present was larger with more observers not agreeing. The inter-observer reliability test on the second read had a mean ICC of 0.94, with a range of 0.90. There were 43 (72%) observations that were the same across all six observers. Of all pairs (915 in total) there was agreement in 804 pairs for the first reading (88%) and disagreement in 111 (12%). For the second reading there was agreement in 801 pairs (86%) and disagreement in 114 (14%). The intra-observer reliability averaged an ICC value of 0.92, with a range of 0.86 to 0.98. The observers agreed with their own previous observations 324 times out of 366 paired readings (89% agreement of pairs).

The COFAS classification of reoperations for end stage ankle arthritis was reliable. This scheme potentially could be applied to other areas of Orthopaedic surgery and should replace the Claiden Dindo modifications that do not accurately reflect Orthopaedic outcomes. As complications are hard to define and lack consistent terminology reoperations and resource utilisation (extra clinic visits, extra days in hospital and extra hours of surgery) may be more reliable measures of the negative effects of surgery.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 24 - 24
1 Dec 2016
Younger A Daniels T Wing K Penner M Veljkovic A Wong H Dryden P Glazebrook M
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Patients often comment on swelling after foot and ankle surgery. However the relationship between swelling and outcome (pain and function) has not previously been outlined. A recent study by Pinsker and Daniels demonstrated that while swelling was rated as important by patients it was rarely included in outcome scores. The purpose of this paper was to determine the relationship between swelling and outcome after ankle fusion or replacement. A secondary purpose was to determine how this relationship changed in time, how swelling score changed before and after surgery, and determine differences in swelling score between total ankle replacement (TAR), open ankle arthrodesis (OAA) and arthroscopic ankle arthrodesis (AAA).

The COFAS prospective ankle arthritis database enrolls patients in 4 centers undergoing surgery by one of 6 surgeons since 2002. The MODEMS outcomes package from AAOS was used, with the validated ankle osteoarthritis score (AOS) score being used to assess outcomes in the pain and disability domains. The swelling score was indexed from 1 to 5, 1 being no swelling and 5 being severe swelling. Outcomes were recorded preoperatively and annually up to 2010. Statistical analysis was performed using 95% confidence intervals and correlations being determined using Pearson's correlation and r2 values.

The swelling score was correlated with AOS score with an r2 of 0.13 for postoperative patients. With the swelling score analysed categorically the difference of outcome was significant with a mean AOS score of 15.1 (CI 13.3 to 16.9) for a swelling score of 1, 23 (CI 21.7 to 24.9) for a swelling score of 2, 31 (CI 29.6 to 33.1) for 33.6 (CI 34.9 to 38.8) for 4, and 39 (CI 35.3 to 43.0) for 5. Swelling scores fell outside the 95% confidence intervals for all groups indicating that the AOS outcome of swelling score 5 patients was worse than the 4 group, 4 worse than 3, 3 worse than 2, and 2 worse than 1. Patients with swelling scores of 1 scored 24 points better than those with a swelling score of 5.

Swelling scores were the same preoperatively for total ankle arthroplasty, Arthroscopic and open fusions. However swelling scores were lower for arthroscopic fusions after surgery for all time periods at an average of 2.1 (CI 1.9 to 2.2), compared to total ankle arthroplasty (2.5, CI 2.4 to 2.6) and open ankle fusion (2.5, CI 2.4 to 2.6).

Swelling has a major relationship with outcome. Swelling may be the cause of poorer outcomes for open ankle fusion compared to arthroscopic. Swelling is an independent factor as swelling scores for TAA were higher compared to AAA despite similar outcomes. Arthroscopic surgery reduces the postoperative swelling. Methods to reduce swelling such as compression stockings, elevation, controlling bleeding may result in better outcomes. Minimising the invasiveness of surgery achieves this goal. Patient education about swelling, elevation and compression stockings would assist in these goals.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_21 | Pages 27 - 27
1 Dec 2016
Younger A Ngai J Penner M Veljkovic A Wing K Wong H
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As an alternative to ankle replacement, ankle arthrodesis remains a mainstay in the treatment of end-stage arthritis. Arthroscopic techniques for ankle arthrodesis have more recently been developed, although there has been limited research exploring the cost of arthroscopic (AAA) versus open ankle arthrodesis (OAA), and comparing ankle fusions to replacement (TAA). We hypothesise that resource use after AAA will be lower than that after OAA, and both will be lower than TAA.

We performed a retrospective review of a prospectively collected database. The COFAS database was used to identify patients with >2 years of follow up who have undergone AAA, OAA or Hintegra TAA at St Paul's Hospital between 2003–2010. Ninety patients with TAA, 52 with AAA and 56 with OAA met our inclusion criteria. The following data were documented: patient demographics (age, gender, presence of diabetes, inflammatory arthritis or any smoking history), factors related to the index surgery (type of surgery, OR time, length of stay) and factors relating to the post-operative course (number of post-operative clinic visits, OR time for re-operations, length of stay for additional hospital admissions).

In terms of the index surgery, AAA required less initial OR time compared to either OAA or TAA. Initial length of hospital stay was significantly longer for both TAA and OAA, compared to AAA. Patients attended more follow-up visits after TAA or OAA compared to after AAA. In terms of additional OR time required, no significant differences were found among the groups. The most common reason for re-operation was infection or wound breakdown (38% of re-operations), followed by removal of hardware (15%). TAA also required significantly more additional days in hospital compared to either OAA or AAA. For all significant comparisons, p < 0.05. For each primary TAA, on average an additional one hour of surgery, three days in hospital and seven clinic visits were required on top of the cost factored for the primary arthroplasty. For each primary AAA, an additional four clinic visits, 23 minutes of revision surgery and one day in hospital were required. For each primary OAA, an average additional five clinic visits, three minutes of OR time, and 0.2 days of additional hospital stay occurred during follow up.

Using several measures of resource use, we find that arthroscopic ankle fusions compare favourably to both ankle replacements and open ankle fusions. We also show that resource utilisation measurements can be a useful surrogate for complications, and that resource utilisation can demonstrate the practical implications of complications for patients, surgeons and health care resources.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 92 - 92
1 Jul 2014
Wong H Chu P Cheung K Luk K Yeung K
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Summary

A promising approach to stimulate in vivo bone formation by using our newly developed magnesium-based bone substitutes, which can be an alternative to treat the patients with bone loss in addition to the anticatabolic drugs and growth factors.

Introduction

Bone impairment arising from osteoporosis as well as other pathological diseases is a major health problem. Anti-catabolic drugs such as bisphosphonates and other biological agents such as bone morphogenetic proteins and insulin-like growth factor can theoretically apply to stimulate bone formation. However, the formation of more brittle bone and uncontrolled release rate are still a challenge nowadays. Hence, we propose to stimulate bone formation by using a newly developed magnesium-based bone substitute. Indeed, the presence of magnesium ions can stimulate bone growth and healing by enhancing osteoblastic activity. This study aims to investigate the mechanical, in vitro and in vivo properties of this novel bone substitute.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 296 - 296
1 Jul 2014
Liu G Tan B Riew D Wong H
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Summary Statement

Tandem stenosis is a prevalent condition in an Asian population with the narrowest cervical canal diameters and risk factors include advanced age and increased levels of lumbar canal stenosis.

Introduction

Tandem spinal stenosis (TSS) is defined as patient with concomitant spinal canal stenosis found in both cervical (C) and lumbar (L) spinal region. Few studies have reported the incidence of TSS is ranged from 5–25%, but these are all noncomparative, small cohort studies. To the best of author knowledge this is the 1st study aims to compare the prevalence of TSS and its risk factors of development in a large multiracial Asian population.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 312 - 312
1 Jul 2014
Malhotra R Kumar N Wu P Zaw A Liu G Thambiah J Wong H
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Summary

Metastatic spinal disease is a common entity of much debate in terms of ideal surgical treatment. The introduction of MIS can be a game-changer in the treatment of MSD due to less peri-operative morbidity and allowing earlier radiotherapy and/or chemotherapy.

Introduction

Less invasive techniques have always been welcome for management of patients with ‘Metastatic Spinal Disorders’. This is because these patients can be poor candidates for extensive / major invasive surgery even though radiologically, there may be an indication for one. The aim of the treatment with Minimal Invasive Fixation (MIS) systems is mainly for ‘pain relief’ than to radically decrease tumour burden or to achieve near total spinal cord decompression, which could be major presentations in these patients. These procedures address the ‘spinal instability’ very well and they can address pain associated with compression fractures resulting from metastatic disease from a solid organ as well as multiple myeloma with minimal complications. These procedures can be combined with radiology and chemotherapy without much concern for wound problems in the way of infection or dehiscence. They also have a great advantage of timing of adjunct therapy closer to the index procedure. The disadvantage, however, are they do not allow thorough decompression of the spinal cord. There could also be problem in addressing patients who have severe vertebral height loss or loss of integrity of the anterior column where anterior column reconstruction may be required. There is a risk of inadequate fixation or implant loosening or failure. We aim to examine the results of MIS surgery in our department and support the rationale for its use.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 310 - 310
1 Jul 2014
Kumar N Chen Y Ahmed Q Lee V Wong H
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Summary

This is the first ever study to report the successful elimination of malignant cells from salvaged blood obtained during metastatic spine tumour surgery using a leucocyte depletion filter.

Introduction

Catastrophic bleeding is a significant problem in metastatic spine tumour surgery (MSTS). However, intaoperative cell salvage (IOCS) has traditionally been contraindicated in tumour surgery because of the theoretical concern of promoting tumour dissemination by re-infusing tumour cells into the circulation. Although IOCS has been extensively investigated in patients undergoing surgery for gynaecological, lung, urological, gastrointestinal, and hepatobiliary cancers, to date, there is no prior report of the use of IOCS in MSTS. We conducted a prospective observational study to evaluate whether LDF can eliminate tumour cells from blood salvaged during MSTS.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 309 - 309
1 Jul 2014
Chen Y Tai B Nayak D Kumar N Goy R Wong H
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Summary

Our meta-analysis showed that pooled mean blood loss during spinal tumour surgeries was 2180 ml. Standardised methods of calculating and reporting intra-operative blood loss are needed as it would be beneficial in the pre-operative planning of blood replenishment during surgery.

Introduction

The vertebral column is the commonest site of bony metastasis, accounting for 18,000 new cases in North America yearly. Patients with spinal metastasis are often elderly, have compromised cardiovascular status, poor physiological reserve and altered immune status, all of which render them more susceptible to the complications of intra-operative blood loss and associated transfusion. Currently no consensus exists regarding the expected volume of blood lost during metastatic spine tumour surgery with various papers quoting anywhere between 1L to 6L. Knowledge of the expected blood loss prior to surgery however is important as it facilitates pre-operative planning, intra- and post-operative management of fluid balance and blood transfusion. We conducted a meta-analysis of published literature on spine tumour surgery to answer the question: “What is the expected blood loss in major spinal tumour surgery for metastatic spinal disease?”


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 311 - 311
1 Jul 2014
Kumar N Chen Y Zaw A Ahmed Q Soong R Nayak D Wong H
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Summary

There is emerging evidence of successful application of IOCS and leucocyte depletion filter in removing tumour cells from blood salvaged during various oncological surgeries. Research on the use of IOCS-LDF in MSTS is urgently needed.

Introduction

Intra-operative cell salvage (IOCS) can reduce allogeneic blood transfusion requirements in non-tumour related spinal surgery. However, IOCS is deemed contraindicated in metastatic spine tumor surgery (MSTS) due to risk of tumour dissemination. Evidence is emerging from different surgical specialties describing the use of IOCS in cancer surgery. We wanted to investigate if IOCS is really contraindicated in MSTS. We hereby present a systematic literature review to answer the following questions: 1. Has IOCS ever been used in MSTS? 2. Is there any evidence to support the use of IOCS in other oncologic surgeries?


Purpose

Femoral nerve block (FNB) following total knee arthroplasty (TKA) has had mixed results with some studies reporting improvement in pain and reduced narcotic exposure while others have not shown substantial differences. The effect of a FNB on rehabilitation indices (quadriceps strength, knee flexion) is also unclear.

The study purpose was to compare the effect of FNB+ a multimodal analgesic protocol (MMA) to MMA only on the 1) development of a complete quadriceps motor block and 2) knee flexion during the first two postoperative days and 3) knee flexion out to 12 weeks after primary TKA. Secondarily, we compared hospital length of stay (LOS), postoperative pain, analgesic use and the incidence of nausea/vomiting.

Method

This was a controlled clinical trial undertaken at two tertiary hospitals that do high annual TJA volumes (>200 cases). Both hospitals followed the same regional clinical pathway for preoperative, perioperative and postoperative care. The pathway started mobilization on the day of surgery with a goal for discharge home on the third postoperative day.

At one site, FNB was used for the first two postoperative days in addition to MMA as needed (FNB group [n=19]) while the other site used standardized MMA (MMA group [n=20]) only.

The presence of a complete quadriceps block, knee flexion, pain, analgesic use, incidence of nausea and vomiting were recorded daily in hospital. Hospital LOS was also recorded and knee flexion and pain were assessed at two, six and 12 weeks post discharge.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 484 - 485
1 Sep 2009
Tan K Moe MM Vaithinathan R Wong H
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Introduction: The natural history of idiopathic scoliosis is not well understood. Previous reports focused on characteristics of curve progression pre-defined at 5–6 degrees. However, the absolute curve magnitude at skeletal maturity is more predictive of long-term curve behavior rather than progression of defined magnitude over shorter periods of growth. It is generally agreed that curves < 30 degrees are unlikely to progress after skeletal maturity. Hence, defining factors that influence curve progression to an absolute magnitude of ≥30 degrees at skeletal maturity significantly aids clinical decision-making.

Methods: Of 279 patients with idiopathic scoliosis detected by school screening of 72,699 adolescents, 186 fulfilled the study criteria and were followed up to skeletal maturity. Initial age, gender, pubertal status and initial curve magnitude were used as predictive factors for curve progression to ≥30 degrees at skeletal maturity. Uni and multivariate, logistic regression and receiver operating characteristic (ROC) analysis was performed.

Results: Curve magnitude at first presentation was the most important predictive factor for curve progression to ≥30 degrees at skeletal maturity. An initial curve of 25 degrees had the best ROC of 0.8 with a positive predictive value of 68% and a negative predictive value of 92% for progression to ≥30 degrees at skeletal maturity. The highest risk was a pre-pubertal female < 12 years of age with a Cobb of ≥25 degrees at presentation; with an 82% chance of progression to a Cobb of ≥30 degrees. Probability of progression to ≥30 degrees was defined by 1/(1 + exp (−z)). [z = −3.709 + 0.931(Gender) + 0.825(Puberty) + 3.314(Cobb) + 0.171(Age)].

Conclusions: Initial curve magnitude is the most important independent predictor of long-term curve progression past skeletal maturity. An initial Cobb of 25 degrees is an important threshold. Combined with other factors, we identify patient profiles with high or low risk for progression.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 486 - 486
1 Sep 2009
Kumar N Guo-Xin N Wong H
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Study Design: A radiographic study using disarticulated cadaver thoracic vertebrae.

Objective: To determine the accuracy of orthogonal X-rays in detecting thoracic pedicle screw position by different groups of observers.

Summary of Background Data: Pedicle screws are increasingly being used for internal fixation of the thoracic spine. Surgeons and radiologists are often required to make decisions on the pedicle screw position by plain antero-posterior (AP) and lateral radiographs.

Materials and Methods: 23 disarticulated fresh adult thoracic vertebrae were used in this study. Pedicle screws were inserted completely within the pedicle; or deliberately violating the lateral or medial cortex of the pedicle. AP and lateral radiographs of each vertebrae were assessed by 2 spine surgeons, 2 spine trainees, and 2 musculoskeletal radiologists in a sequence of AP alone, and AP + lateral views. They were supposed to cataogorize the pedicular screw as ‘out laterally’/‘inside the pedicle’/‘out medially’ or ‘unsure’. Their assessments were compared to the actual position of the screws determined by the axial views.

Results: For each screw position, trend was found towards slightly better accuracy with availability of AP & lateral views in combination. From either AP alone or AP + lateral views, significantly higher accuracy was found in detecting screws “out laterally” than “inside pedicle” (p< 0.01), or “out medially”(p< 0.05), respectively. Nearly 30% of screws that were deliberately placed through the medial pedicle wall were not correctly identified. In addition, surgeons have highest accuracy from either AP alone, or AP + lateral views, followed by the spine trainees and radiologists. Radiologists provided more “unsure” answers than surgeons or trainees.

Conclusions: Screws that perforated the lateral cortex were the easiest, and those that were wholly within the pedicle were the most difficult to identify correctly. The use of plain radiographs to detect thoracic pedicle screws placed through the critical medial cortex is unreliable. The positions of thoracic pedicle screws appear to be more accurately detected by AP + lateral, however, the major contribution was from AP views. Surgeon experience continues to be vitally important in the safe placement of thoracic pedicle screws.

Key points:

Screws that perforated the lateral cortex were the easiest, and those that were wholly within the pedicle were the most difficult to identify correctly.

The use of plain radiographs to detect thoracic pedicle screws placed through the critical medial cortex is unreliable.

AP + lateral views provides higher accuracy in determining the screw position, while, the major contribution comes from AP views.

Surgeon experience, in the use of tactile skills and anatomical knowledge continue to be vitally important in the safe placement of thoracic pedicle screws.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 489 - 489
1 Sep 2009
Ruiz J Hernstadt H Lim L Lim W Hee H Wong H
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Patient outcomes using the Scoliosis Research Society (SRS) questionnaire after thoracoscopic and posterior surgical techniques for thoracic idiopathic scoliosis were compared after > 2 years post-op. Additional comparisons were made with non-operated scoliosis and normal patients. Our objective was to determine if scoliosis surgery and surgical technique used to treat a cohort of patients with the same type of scoliosis deformity affects patient outcome. The SRS-24 questionnaire was prospectively administered to 4 groups of patients:

42 patients with thoracic idiopathic scoliosis who underwent thoracoscopic instrumented fusion surgery (thoracoscopic group);

42 patients with thoracic scoliosis who underwent posterior instrumented fusion surgery (posterior group);

97 patients with thoracic scoliosis who did not have surgery (scoliosis control group);

72 patients who did not have scoliosis (normal group).

The 2 surgical groups were comparable with regards to age at surgery, pre-op Cobbo and follow-up. SRS-24 domian scores were computed for all 4 groups and were compared on SPSSv13 software. Our results show the thoracoscopic group having a significantly smaller mean post-op Cobbo (17° vs 25.1°, respectively; p< .001), which was achieved using less fusion segments (7 vs 9.3 segments, respectively; p< .001). The mean Cobbo of the scoliosis control group was significantly larger than the post-op Cobbo of the thoracoscopic group (p< .001), and was comparable to the post-op Cobbo of the posterior group. Comparing the 2 surgical groups, the thoracoscopic group showed trends towards better scores in 4 of the SRS-24 domains compared to the posterior group, but this only reached statistical significance for the satisfaction domain (p< .05). When comparing the 4 groups, Pain scores of both surgical groups were similar to those who did not have surgery, and were worse than normal patients (p< .0001); Self-image scores after surgery were higher than those who did not have surgery(p< .05) and were comparable to normal patients; Function and Activity scores of the thoracoscopic group was significantly inferior to the scoliosis control group (p< .05). Our study demonstrates that > 2 years after surgery, both thoracoscopic & posterior surgery resulted in pain scores that were similar to patients with scoliosis that did not have surgery, and were worse than the normal group. However, both surgical techniques resulted in self-image scores that are comparable to normal individuals despite a difference in post-op Cobbo. When comparing the two surgical techniques, the SRS-24 showed no difference between the 2 surgical techniques, except for patient satisfaction which was better in the thoracoscopic group.


Posterior instrumented fusion is an established surgical treatment for majority of AIS cases. In the past decade, thoracoscopic instrumentation and fusion has emerged as a viable alternative to conventional posterior techniques in situations that require selective thoracic fusion. Most reports comparing the two techniques have focused on physician-based outcomes such as curve correction and maintenance of the surgical correction with both methods being comparable. Recently, the SRS-24 has been used to evaluate patient-based outcomes after scoliosis surgery. The instrument assesses seven equally-weighted domains that look at pain, self-image, general function, activity level, change in self-image and function post-surgery, and satisfaction with the procedure. It has been used to evaluate differences between AIS and normal patients, and in different degrees of AIS deformity. The instrument has not been used in comparing different methods of surgical treatment for similar curve types.

We applied the SRS-24 prospectively to our patients who had undergone either thoracoscopic (TG) or posterior (PG) instrumented fusion, and had been followed-up for at least 12-months postoperatively. There were 42 patients in TG and 42 patients in PG. The mean age at time of surgery, pre-operative Cobb angles, and number of spinal segments fused were similar in both groups. The mean follow-up period at the time the SRS instrument was administered was 26 (± 13.5) months for TG and 30.7 (± 12.1) months for PG. The postoperative Cobb angle on the latest follow-up was significantly better for TG compared to PG (17 versus 25.1 degrees, respectively; p < .001). Upon comparing the SRS domain scores between both groups, a significant difference was noted only in the patient satisfaction domain with TG scoring better than PG (p < .02).

The first four SRS-24 domain scores for TG and PG were also compared to the corresponding domain scores of 97 patients who had scoliosis but were not candidates for surgery (SG), as well as to the scores of 72 patients who did not have scoliosis (NG). SG, TG, and PG were comparable with regards to pain and all three were significantly lower compared to NG (F=14.828, p < .0001).

General function and activity level scores of TG were significantly lower compared to the other three groups (F=4.870, p < .003 and F=4.793, p < .003, respectively). Despite this, the self-image domain scores of both TG and PG were not significantly different from NG, with SG scoring significantly poorer compared to the other three groups (F=3.183, p < .02).

In summary, thoracoscopic instrumented fusion resulted in better curve correction compared to posterior instrumented fusion and was achieved with less spinal segments being fused. This was despite the finding that patients who underwent thoracoscopic surgery had lower physical function and activity level scores. Additionally, both surgical techniques resulted in patients whose perception of themselves was comparable to those patients who did not have scoliosis. The SRS-24 was not able to detect any differences between the two surgical methods in all domains except for overall patient satisfaction which was significantly better in the thoracoscopic group.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_III | Pages 441 - 442
1 Aug 2008
Hee H Yu Z Wong H
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Anterior instrumentation is an established method of correcting King I adolescent idiopathic scoliosis. Posterior segmental pedicle screw instrumentation, with its more powerful corrective force over hooks, could offer significant advantages. The purpose of our study is to compare the results of anterior instrumentation versus segmental pedicle screw instrumentation in adolescent idiopathic thoracolumbar scoliosis. A retrospective analysis was conducted on 36 consecutive female patients with adolescent idiopathic thoracolumbar scoliosis who had surgery from December 1997. All had a minimum of two year follow-up. Eleven patients had posterior surgery performed on them.

Mean age at surgery was similar between both groups. Length of surgery was significantly shorter in the posterior group (189 minutes versus 272 minutes). Length of hospital stay was shorter in the posterior group (6.2 days versus eight days). Estimated blood loss, duration of analgesia, and ICU stay did not differ significantly between the two groups. No complications were encountered in both groups at latest follow-up. The magnitudes and flexibility of the thoracolumbar curves did not differ significantly between the two groups. The number of levels in the major curve was also similar between the groups. Fusion levels were shorter in the anterior group (mean 4.1 versus 5.0). The percentage correction of scoliosis was similar between the two groups at all stages of follow-up, being 74% at one week post-surgery, 70% at six months post-surgery, 68% at one year post-surgery and latest follow-up in the anterior group; and 71% at one week post-surgery, 67% at six months post-surgery, 68% at one year post-surgery, and 67% at latest follow-up in the posterior group.

Thoracolumbar sagittal alignment at T11 to L2 was maintained for both groups throughout the follow-up period. The incidence of proximal junctional kyphosis was higher in the posterior group (p < 0.01).

In conclusion, surgical correction of both the frontal and sagittal plane deformity are comparable to anterior instrumentation. Shorter length of surgery and hospital stay are the potential benefits of posterior surgery. Posterior segmental pedicle screw instrumentation offers significant advantage, and is a viable alternative to standard anterior instrumentation in idiopathic thoracolumbar scoliosis.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_III | Pages 442 - 442
1 Aug 2008
Wong H Hee H Yu Z
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Thoracoscopic spinal instrumentation and fusion has emerged as a viable alternative to open anterior and posterior techniques for the treatment of thoracic adolescent idiopathic scoliosis. Furthermore, the morbidity associated with thoracoscopy is limited, and the cosmetic result more desirable because of the minimal skin and chest wall dissection required with this method. However, the technique is technically demanding and has been perceived as having a steep learning curve. The objective of our study is to anal the initial series of 50 patients performed by a single surgeon, with respect to the coronal and sagittal alignment on radiographs, as well as a review of the peri-operative data and complications.

Fifty consecutive patients who underwent thoraco-scopic instrumentation and fusion were divided into two groups for the purpose of this study: the first 25 cases (1st group) and the second 25 cases (2nd group). The minimum follow-up of these cases was 12 months (range 12 to 67 months). Data collected included the operative time, intra-operative blood loss, number of levels instrumented, length of the hospital stay, the number of days in the ICU, and the duration of analgesia.

No major complications, such as neurological deficit, vascular injury, or implant failure were observed. No significant difference was encountered between the groups in terms of age and menarche at surgery, pre-operative curve magnitude and flexibility, sagittal profile, as well as the number of levels in the curve pre-operatively. The second group had significantly better coronal deformity correction at one week post-operatively (9.5 degrees versus 16.3 degrees, p < 0.001), six months post-operatively (12.1 degrees versus 18.9 degrees, p < 0.001), and at latest follow-up (15.1 degrees versus 19.5 degrees, p < 0.05). The percentage correction of scoliosis was significantly better in the second group at one week postoperatively (p < 0.001), six months post-operatively (p < 0.001), and at latest follow-up (p = 0.014). The percentage change in thoracic kyphosis and lumbar lordosis after surgery was not significantly different between both groups at various times of follow-up. There was no difference between both groups with regards to the number of levels fused, hospital stay, and duration of parenteral analgesia. Operative time was significantly less in the second group (302 minutes versus 372 minutes, p < 0.001). Estimated blood loss was also less in the second group (170 cc versus 266 cc, p = 0.04). The length of ICU stay was also shorter in the second group (1.8 days versus three days, p = 0.004). From the loess (locally-weighted regression) fit, the learning curve is estimated to be 30 cases with regards to the operative time, ICU duration, and the coronal plane deformity correction.

The learning curve associated with thoracoscopic spinal instrumentation is acceptable. The complication rates remained stable throughout the surgeon’s experience. Thoracoscopic anterior instrumented fusion is a viable surgical alternative to standard posterior fusion and instrumentation for adolescent idiopathic scoliosis requiring selective thoracic fusion.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 235 - 236
1 Sep 2005
Wong H Moe M Vaithinathan R
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Study Design: Prospective cohort study

Objective: To determine the rate of curve progression and factors related to curve progression in untreated adolescent idiopathic scoliosis in a prospective cohort study within a national school screening program.

Methods: Over 140,000 school children are screened annually in Singapore for common health conditions, including scoliosis. In 1996–97, a randomized sample in four age groups consisting of 72,699 children was enrolled in a scoliosis prevalence study, 263 were found to have spinal curvatures of 10 degrees or more. After exclusions, 250 children were followed up over a five year period up to 2001–02. Basic demographic data, age at menarche or break of voice, scoliometer reading, curve type, Cobb angle, curve rotation, and Risser grade were recorded. Curve progression was correlated to individual factors such as age, sex, puberty, curve type and magnitude as well as combinations of factors.

Results: Overall, 28% of the 250 curves progressed. Age at diagnosis, sex, pre-menarche status, and curve magnitude were statistically correlated to curve progression. Taking curve magnitude and age together, 53% of 11–12 year-olds with curves 20 degrees or more progressed compared to 10% of 13–14 year-olds with curves less than 20 degrees. 56% of children with curves 20 degrees or more and Risser grades 0–2 progressed, compared to 17% with curves less than 20 degrees and Risser grades 3–5. Combining curve magnitude, age, sex, and puberty together, a pre-pubertal female under 13 years old with a curve of 25 degrees or more has a 70% chance of curve progression. In comparison, a post-pubertal female older than 13 years of age and a curve of less than 25 degrees has only a 10% chance of progression. Curve progression in adolescent idiopathic scoliosis has been reported to vary from 5.2% to 56%, with the lower rates being found in school screening studies. Nachemson et al (1982) reported that 10–12 year old girls with untreated scoliosis of 20–29 degrees had a 60% risk of curve progression. Lonstein and Carlson (1984) reported progression in 23.2% of untreated children and that curve magnitude, skeletal immaturity, and curve pattern were associated with progression.

Conclusions: Our findings are similar, with pre-pubertal females under the age of 13 years old and with large curves at diagnosis having the greatest risk of progression.


Study Design: Compartative cohort study.

Objective: To compare the safety and efficacy of conventional posterior instrumented fusion versus thoracoscopic instrumented fusion for the surgical treatment of King Type III adolescent idiopathic scoliosis.

Methods: The results of 34 consecutive patients with King type 3 scoliosis treated with one of the above techniques were analyzed independantly. Twenty-two patients underwent posterior spinal fusion (PSF) and instrumentation (Moss-Miami). Twelve patients had thoracoscopic fusion (TF) and instrumentation (Eclipse).

Results: Baseline demographics (age at menarche and surgery, pre-operative Cobb angles in coronal and sagittal planes), estimated blood loss at surgery and duration of parenteral analgesia did not differ between the two groups. PSF patients had significantly higher transfusion requirements (p=0.032). Operative time (p = 0.0001), ICU stay (p = 0.005), and hospital stay (p = 0.037) were longer in TF cases. There were no complications in PSF patients. Complications in TF patients included lobar collapse (1 patient) and scapula winging (1 patient). Improvement in scoliosis among PSF patients averaged 75% (1 week), 70% (6 months), and 65% (1 year). In TF patients, mean improvement in scoliosis was 66% (1 week), 62% (6 months), and 62% (1 year). The differences between the two groups in terms of scoliosis improvement were not significant. Curves with apex at T8 or higher had better correction of scoliosis (p = 0.05). The sagittal alignment (thoracic kyphosis and lumbar lordosis) after surgery was similar between the two groups at 1 week, 6 months, and 1 year post-operatively.

Conclusion: The efficacy of thoracoscopic anterior fusion and instrumentation is similar to standard posterior instrumented fusion. The advantages of the thoracoscopic technique are the avoidance of a long posterior midline scar, and lower transfusion requirement. A longer operative time, ICU and hospital stay was attributed to the steep learning curve of this endoscopic technique.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 239 - 239
1 Nov 2002
Thacker M Hui J Wong H Lee E
Full Access

Introduction: Surgery in patients with neuromuscular scoliosis is aimed at improving truncal balance, facilitating sitting, prevention of progression of the curve and preservation of respiratory function.

Patients and Methods: This was a retrospective study of surgical results in a group of 24 patients with minimum follow up of 2 years an average post-operative follow up of 5 years (2–9 years) with neuromuscular scoliosis due to varying aetiologies. The aetiologies included SMA (7), CP (6), Duchenne (5), Congenital Myopathies (3), Spina Bifida (2) and Paraspinal Neuroblastoma (1).

Results: The average age at surgery was 10.6 years, the average duration was 4hrs 25mins with an average blood loss pf 1.1 liters. An average ICU stay was 1–2 days and stay in hospital is 11 days. The curves ranged from 25–103° (average 75.6°) pre-operative and we were able to obtain a correction of 56%. In all but 2 of our patients we were successful in preventing deterioration of respiratory function and all our patients could at least sit without support post-operatively. Our complications included only one deep infection (necessitating implant removal), 1 rod breakage and 2 patients with UTI. There were no significant respiratory complications in post-operation.

Conclusion: Spinal surgery in patients with neuromuscular scoliosis is safe and prevents deterioration of respiratory and improve truncal balance and hence quality of life.