INTRODUCTION: Tarlov first described the sacral perineural cyst in 1938 as an incidental finding at autopsy. There is very little data in the literature regarding the natural history of Tarlov cysts and consequently the recommendations for treatment are vague. Various operative treatments have been suggested including cyst aspiration, cyst decompression, microsurgical cyst imbrication and cyst plication with cement filling of bony defects. We were first presented with the difficulty of managing a patient with a large symptomatic sacral cyst in 1997 and found little in the literature to help advise the patient. This paper presents the results of a prospective observational study and describes the clinical relevance of the different types of cyst, showing how a simple clinico-radiological classification can be used to help manage patients with cysts. METHODS: Between February 1997 and December 2002, 3935 patients underwent standard three sequence MRI scanning (T1 and T2 sagittals and T2 axials) for lumbosacral symptoms in our hospitals. 62 patients had cysts in their sacral canals, an incidence of 1.6%. Additional contiguous axial and coronal scan sequences were carried out to fully characterise them. Once identified, the clinical picture was correlated with the findings on MRI. RESULTS: Tarlov cysts can be classified according to whether or not their presence is related to clinical symptoms. Type 1 cysts (n=38; 61%) are small, often multiple and are found at the most distal sacral segments. They are entirely unrelated to the patient’s symptoms and require no specific treatment. This has been confirmed when the primary pathology has been treated and the patient’s symptoms have been alleviated. Type 2 cysts (n=13; 21%) are usually single, unilateral and occur at the same level as the main cause of the patient’s symptoms, often a prolapsed intervertebral disc at L5/S1 with a Tarlov cyst in the S1 root canal. As such, the cyst itself will not require any treatment, which should be directed at the main pathology. Type 3 cysts (n=11; 18%) are the main cause of the patient’s symptoms and may require specific treatment. We have found that more than half of the Type 3 cysts can be managed expectantly with serial clinical and MRI review. However, the majority of these cysts (9 of 11) are massive and can cause both erosion of bone and compression of the lower sacral nerve roots. Three have to date required decompression to treat cauda equina symptoms. CONCLUSIONS: The majority of Tarlov cysts are incidental findings on MRI. They may, however, either contribute to, or be responsible for, a patient’s symptoms. Our classification system addresses this and offers guidance on patient management.
INTRODUCTION: The initial promise of stand-alone threaded anterior interbody fusion cages to treat chronic low back pain has not been maintained. In an attempt to overcome some of the problems associated with threaded fusion devices (endplate subsidence, failure to re-establish lordosis and displacement) a two-part ALIF cage was devised. The device consists of a rectangular frame that accommodates a threaded, open-weave cylinder holding bone graft material. The device addresses the biomechanical issues required for successful ALIF whilst providing a large area for bone in-growth and is a less invasive solution than a formal 360° fusion. METHODS: From August 2001 to December 2002, 41 patients who fulfilled selection criteria for a single or two-level 360° spinal fusion for low back and leg symptoms underwent ALIF using Stabilis. All patients had failed to improve with all non-invasive and minimally invasive treatments available to them. Prospective follow-up has continued for all cases using the Low Back Outcome Score and a Patient Satisfaction Score. Plain X-rays were taken at three, six and 12 months post-operatively and the 12-month series included flexion and extension films. RESULTS: Ten patients (24.4%) have completed more than 12 months follow-up; 18 (43.9%) are between six and twelve months post surgery and the rest (31.7%) have less than six months follow-up. LBOS results for the first 10 showed nine (90%) as excellent or good. LBOS results for the second group of 18 were excellent or good in 15 (83.3%). All but two of the 28 patients, would be prepared to undergo the procedure again and all would recommend the operation to a friend with similar trouble. Radiographic assessment at six months showed 16 patients had at least a partial anterior or posterior sentinel sign. Using motion criteria, all 10 cases at one year were fused on flexion and extension lateral X-rays. No devices migrated anteriorly or posteriorly and no lucent lines have been seen around the implants. Three of the two-level procedures showed some subsidence of the L4/5 implant into the L5 vertebral body, but none was symptomatic. No clear reasons have emerged to explain the clinical failure of 14% of the patients given the radiological success. In only one was there a mismatch in the LBOS outcome measure and the satisfaction rating. CONCLUSIONS: Stabilis is a useful stand-alone ALIF device that not only addresses the theoretical biomechanical failures of anterior threaded interbody fusion cages, but has been shown in this early clinical and radiological evaluation to be effective, objectively and subjectively. It is likely that in the medium term future, fewer patients will require fusion to treat back and leg pain as the results from lumbar spine arthroplasty become established and non-fusion technologies become accepted. Until that time, experience in the UK and USA suggests that Stabilis is a good alternative to 360° fusion.
INTRODUCTION: No previous cases of avascular necrosis (AVN) of the femoral head have been described in the World Literature, to our knowledge. This paper reports the catastrophic failure of the bony integrity of the hip in three patients (five hips) following prolonged hypotension during spinal surgery for spinal stenosis on a Montreal mattress and offers advice to prevent this complication of spinal surgery. A theory to explain this phenomenon is explored, but we recognise its limitations with such a small sample. METHOD: The case notes of all patients undergoing decompressive spinal surgery in our hospitals between March 1997 and December 2001 were examined (168 cases). Three patients had been identified as suffering from AVN following prolonged hypotensive anaesthesia prospectively. No other cases were identified after the notes review. Clinical notes and pre- and post-operative radiographs were studied in an attempt to identify the factors that caused this complication in these three patients. RESULTS: Between 1997 and 2001, 168 patients underwent surgery for multi-level symptomatic spinal stenosis in our hospitals. Forty percent of the patients had an instrumented fusion as well as a decompression. During this period, three patients had catastrophic AVN of the femoral head requiring total hip arthroplasty soon after their spinal operation. All had some clinical and radiological evidence of hip arthritis at their pre-surgery visit. All subsequently, presented with symptomatic hip AVN within six months of the index operation. In two, histology confirmed the diagnosis of AVN, and typical changes of AVN were well demonstrated on MRI in the third patient. CONCLUSIONS: The development of avascular necrosis of the femoral heads following surgery for spinal stenosis may be due to a femoral head at risk being exposed to hypotensive anaesthesia, prone positioning on a Montreal mattress or a combination of the two. Careful intra-operative positioning may reduce the risk of this occurring after spinal surgery. However, close post-operative surveillance and a high index of suspicion of worsening hip pathology in patients who appear to mobilise poorly after lumbar spinal surgery may be the only method of early detection of this condition.
INTRODUCTION: Recent evidence from the Swedish Lumbar Spine Group has confirmed the anecdotal opinions of many spinal surgeons that fusion for persistent back pain can be a very effective treatment. However, it is clear that many more variables operate in determining clinical success than just radiological evidence of solid fusion. The very careful selection of patients for low back surgery is, in the opinion of the authors, the most important predictor of success. This paper addresses this issue and presents data to show why clinical failure can coexist with radiological success. METHODS: Between October 1997 and January 2001, 360° spinal fusion using Diapason pedicle screw instrumentation and Brantigan anterior interbody fusion cages was performed on 25 patients. During this period 5,850 new outpatients with back pain were assessed in the low back clinic. Patients were selected by the following criteria: Low back pain of two years or more duration; Pain resistant to all non-operative and minimally invasive treatments; Normal psycho-social profile; Normal body mass index; Non-Smokers; Single or two level disease on MRI proven to be painful by provocative discography; No current insurance or workers-compensation claims. Postal follow-up was at a minimum of two years post-surgery (mean 47 months) using the Low Back Outcome Score (LBOS) and X-rays taken at the two-year clinic follow-up were independently assessed to determine fusion. RESULTS: 24 patients returned the questionnaire (96%). Only 20 (83%) patients had ‘good’ or ‘excellent’ results, as defined by the LBOS. However, 92% of patients stated that they would opt to have a circumferential fusion again, if guaranteed the same post-operative result. The same number of patients stated they would recommend the treatment to friend or family member. Analysis of the post-operative radiographs revealed that spinal fusion (as defined by the Brantigan and Steffee criteria) was present in all 25 cases. CONCLUSIONS: Our opinion that patient selection is the most important predictor of satisfactory outcome in spinal surgery is demonstrated in this study by the mismatch between the clinical and radiological results. We have identified the causes of clinical failure in this group of patients as: Multiple sites of musculo-skeletal pain confounding the LBOS; Neuropathic leg pain that cannot respond to surgical treatment; More than two previous spinal operations; Excessive pre-operative disability and functional loss that confounds the LBOS; Poor psychosocial profile. Stringent application of rigid selection criteria might improve outcomes in lumbar spinal fusion so that clinical and radiological results correlate more closely. However, even with adherence to such rigid criteria, the outcome tool (LBOS) may be confounded and a more holistic assessment of outcome, including a more sensitive subjective assessment of satisfaction, might be a better measure.
INTRODUCTION: Discectomy for herniation of the nucleus pulposus is an effective procedure when conservative treatment has failed. However, a number of patients rapidly progress to symptomatic instability after discectomy. Those most likely to develop instability have central and multi-regional herniations. Therefore, primary posterior lumbar interbody fusion (PLIF) may be a better option than discectomy alone in this group. This paper presents the clinical and radiological outcome of a consecutive group of such patients treated in one centre by PLIF, but recognises that newer technologies may make such destructive spinal surgery unnecessary in the future. METHODS: Between June 1997 and December 2000, PLIF for central disc herniation presenting with acute, sub-acute and chronic back and leg pain, with or without neurological loss, using Diapason pedicle screw instrumentation and Ogival PEEK (Poly-ether-ether-ketone) Interbody Fusion cages was performed on 41 patients. Eight patients presented acutely with cauda equina symptoms and 33 patients had sub-acute or chronic symptoms. Formal clinic follow-up was continued for at least two years post-surgery and the final outcome at two to five years after operation was assessed using the Low Back Outcome Score (LBOS). Two independent orthopaedic surgeons assessed the radiological evidence of fusion on X-rays taken at least two years after surgery. RESULTS: 39 of the 41 patients completed the LBOS questionnaire (95%). One patient had died from an unrelated cause and the other could not be contacted having moved away. 34 (87%) of these had an excellent or good outcome according to the LBOS criteria. However, every patient who returned the questionnaire stated that they would undergo the operation again if guaranteed the same surgical result and all would recommend it to a friend for similar trouble. Four patients (9.7%) were dissatisfied with the process of care they experienced. Analysis of radiographs taken between two and four years post-operatively revealed that spinal fusion (as defined by the Brantigan and Steffee criteria) was present in 38 cases (92.7%). None of the patients with a non-union radiologically had a poor outcome. CONCLUSIONS: Post-discectomy instability causing disabling low back and leg pain is more likely to occur in patients with an incompetent annulus than those with a largely intact annulus. The patients in this series all had good evidence on MRI of complete (pan-annular) failure. The decision to perform an acute single level PLIF was taken after discussion with the patients, presenting them with the option of having only a central discectomy and a later fusion if needed or of dealing with the problem at one operation. The outcomes described in this study show that this condition is a good indication for PLIF. However, newer technologies such as disc arthroplasty may be a better option for this group of patients in the future.
We report a prospective, randomised, controlled trial of the effect of either a non-steroidal anti-inflammatory drug (diclofenac sodium) or physiotherapy on the recovery of knee function after arthroscopy. At 42 days after surgery there was no significant benefit from either form of postoperative treatment compared with the control group. Complications attributable to the anti-inflammatory drug occurred in 9.6% of the patients so treated. Neither the routine administration of a non-steroidal anti-inflammatory agent nor routine physiotherapy is justified after arthroscopy of the knee.
