Aims

We compared decompression alone to decompression with fusion surgery for lumbar spinal stenosis, with or without degenerative spondylolisthesis (DS). The aim was to evaluate if five-year outcomes differed between the groups. The two-year results from the same trial revealed no differences.

A clinical retrospective study was conducted. Results of isolated decompression for degenerative lumbar stenosis was compared with the outcome in patients who underwent decompression-stabilisation. From January 1992 to December 2002, 127 patients (average age 65.5) with lumbar degenerative stenosis surgically treated were studied. In all patients the Roy-Camille technique was used for decompression; in 41 patients decompression and posterior stabilisation procedures were carried out. Average follow-up was 6 years (range 2–11 years). The outcomes, evaluated according to Lassale classification, were satisfactory in 81% of the decompressed group while improved to 88% in the stabilised–decompressed group. Three patients of the first group required stabilisation for intractable low back pain (one patient) and lumboradicular symptoms (two patients), while problems related to the device (one hardware failure) and two instances of adjacent segmental instability were seen in the second group. Decompression alone is associated with an increased rate of residual low back pain (one patient in this cohort required fusion). The decompression–stabilisation procedure reduces the incidence of low back pain but is associated with other complications such as significant blood loss, possible wound infections, urinary tract infections (due to increased surgical time), device failures, root impingement and late adjacent segmental pathologies. The Roy Camille technique is effective for achieving adequate decompression. The surgeon should always be aware of patients who might require fusion. The instrumented stabilisation should be reserved for patients with chronic low back pain and evident instability, degenerative spondylolisthesis and spine deformities such as scoliosis or kyphosis

Aims

To compare the efficacy of decompression alone (DA) with i) decompression and fusion (DF) and ii) interspinous process device (IPD) in the treatment of lumbar stenosis with degenerative spondylolisthesis. Outcomes of interest were both patient-reported measures of postoperative pain and function, as well as the perioperative measures of blood loss, operation duration, hospital stay, and reoperation.

Symptomatic lumbar spinal stenosis is a common entity and increasing in prevalence. Limited evidence is available regarding patient reported outcomes comparing primary vs revision surgery for those undergoing lumbar decompression, with or without fusion. Evidence available suggest a lower rate of improvement in the revision group. The aim of this study was to assess patient reported outcomes in patients undergoing revision decompression, with or without fusion, when compared to primary surgery.

Patient data was collected from the Canadian Spine Outcomes Research Network (CSORN) database. Patients undergoing lumbar decompression without or without fusion were included. Patients under 18, undergoing discectomy, greater than two level decompressions, concomitant cervical or thoracic spine surgery were excluded. Demographic data, smoking status, narcotic use, number of comorbidities as well as individual comorbidities were included in our propensity scores. Patients undergoing primary vs revision decompression were matched in a four:one ratio according to their scores, whilst a separate matched cohort was created for those undergoing primary vs revision decompression and fusion. Continuous data was compared using a two-tailed t-test, whilst categorical variables were assessed using chi-square test.

A total of 555 patients were included, with 444 primary patients matched to 111 revision surgery patients, of which 373 (67%) did not have fusion. Patients undergoing primary decompression with fusion compared to revision patients were more likely to answer yes to “feel better after surgery” (87.8% vs 73.8%, p=0.023), “undergo surgery again” (90.1% vs 76.2%, P=0.021) and “improvement in mental health” (47.7% vs 28.6%, p=0.03) at six months. There was no difference in either of these outcomes at 12 or 24 months. There was no difference between the groups ODI, EQ-5D, SF 12 scores at any time point. Patients undergoing primary vs revision decompression alone showed no difference in PROMs at any time point.

In a matched cohort, there appears to be no difference in improvement in PROMS between patients undergoing primary vs revision decompression, with or without fusion, at two year follow-up. This would suggest similar outcomes can be obtained in revision cases.

The purpose of the study was to evaluate if use of the ArthroCare Radiofrequency Ablation Wand caused excess heating and collateral damage to the surrounding tissues during Arthroscopic Subacromial Decompression. Cadaveric studies have shown worryingly high temperatures are reached when using Radiofrequency Ablation Wands in arthroscopic shoulder surgery. We are unaware of any published literature which assesses these temperature rises in the clinical setting. 10 patients were recruited to participate in the study. A standard Arthroscopic Subacromial Decompression was performed using continuous flow irrigation with intermittent use of the Radiofrequency Ablation Wand for soft tissue debridement. The temperature of the irrigation fluid in the subacromial bursa and the outflow fluid from the suction port of the wand were measured continuously during the procedure using fibre-optic thermometers. Temperatures above 45oC in the subacromial bursa were deemed to be unsafe. The mean peak temperature recorded in the subacromial bursa was 28.6oC (23.49 – 31.94oC) with a mean rise from baseline of 6.1oC. The mean peak temperature recorded from the outflow fluid from the wand was 73.1oC (69.09 – 76.1oC) with a mean rise from baseline of 47.66oC. Significantly high temperatures were noted in the outflow fluid from the wand but this was not evident in the subacromial bursa itself. Although high temperatures are generated at the tip of the wand this does not appear to be transmitted to the surrounding irrigation fluid in the subacromial bursa. We therefore conclude that safe temperatures are maintained within the bursa when using this device, thereby minimizing damage to the surrounding tissues, meaning collateral thermal damage is unlikely

Objective

Lumbar spinal stenosis (LSS) is a common spinal disorder mostly caused by the arthritic process. In cases with refractory complaints or significant neurologic deficit, decompressive surgery with or without instrumented fusion may be indicated. We aimed to investigate the surgical outcome of multi-level LSS in the patient with stable spine treated by simple decompression versus decompression and instrumented fusion. Methods: We retrospectively studied 51 patients (25 male, 26 female) with stable multi-level (>2 levels) LSS who were treated by decompressive surgery alone (group A, 31 cases) and decompression and instrumented fusion (group B, 20 cases) and followed them for more than two years. The patients’ disability and pain were assessed with Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS), respectively. At the last follow-up visit, patient satisfaction with surgery was also scored. Results: The two groups were homogeneous in terms of age, sex, severity of disability and pain. Surgery could significantly improve pain and disability in both groups. Preoperative ODI in group A and B were 51.0±23.7 and 54.5±22.9, respectively, however at the last follow-up visit these parameters improved to 23.1±21.1 and 36.6±21.4 showing a statistical significance. Mean patient satisfaction with surgical intervention was also higher in the simple decompression group, but this difference was not significant. Conclusion: In surgical treatment of the patients with multi-level but stable LSS, simple decompression versus decompression and instrumented fusion could achieve more disability improvement for more than two years of follow-up.

Spinal stenosis is a condition resulting in the compression of the neural elements due to narrowing of the spinal canal. Anatomical factors including enlargement of the facet joints, thickening of the ligaments, and bulging or collapse of the intervertebral discs contribute to the compression. Decompression surgery alleviates spinal stenosis through a laminectomy involving the resection of bone and ligament. Spinal decompression surgery requires appropriate planning and variable strategies depending on the specific situation. Given the potential for neural complications, there exist significant barriers to residents and fellows obtaining adequate experience performing spinal decompression in the operating room. Virtual teaching tools exist for learning instrumentation which can enhance the quality of orthopaedic training, building competency and procedural understanding. However, virtual simulation tools are lacking for decompression surgery. The aim of this work was to develop an open-source 3D virtual simulator as a teaching tool to improve orthopaedic training in spinal decompression. A custom step-wise spinal decompression simulator workflow was built using 3D Slicer, an open-source software development platform for medical image visualization and processing. The procedural steps include multimodal patient-specific loading and fusion of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) data, bone threshold-based segmentation, soft tissue segmentation, surgical planning, and a laminectomy and spinal decompression simulation. Fusion of CT and MRI elements was achieved using Fiducial-Based Registration which aligned the scans based on manually placed points allowing for the identification of the relative position of soft and hard tissues. Soft tissue segmentation of the spinal cord, the cerebrospinal fluid, the cauda equina, and the ligamentum flavum was performed using Simple Region Growing Segmentation (with manual adjustment allowed) involving the selection of structures on T1 and/or T2-weighted scans. A high-fidelity 3D model of the bony and soft tissue anatomy was generated with the resulting surgical exposure defined by labeled vertebrae simulating the central surgical incision. Bone and soft tissue resecting tools were developed by customizing manual 3D segmentation tools. Simulating a laminectomy was enabled through bone and ligamentum flavum resection at the site of compression. Elimination of the stenosis enabled decompression of the neural elements simulated by interpolation of the undeformed anatomy above and below the site of compression using Fill Between Slices to reestablish pre-compression neural tissue anatomy. The completed workflow allows patient specific simulation of decompression procedures by staff surgeons, fellows and residents. Qualitatively, good visualization was achieved of merged soft tissue and bony anatomy. Procedural accuracy, the design of resecting tools, and modeling of the impact of bone and ligament removal was found to adequately encompass important challenges in decompression surgery. This software development project has resulted in a well-characterized freely accessible tool for simulating spinal decompression surgery. Future work will integrate and evaluate the simulator within existing orthopaedic resident competency-based curriculum and fellowship training instruction. Best practices for effectively teaching decompression in tight areas of spinal stenosis using virtual simulation will also be investigated in future work

Aims

The aims of this study were first, to determine if adding fusion to a decompression of the lumbar spine for spinal stenosis decreases the rate of radiological restenosis and/or proximal adjacent level stenosis two years after surgery, and second, to evaluate the change in vertebral slip two years after surgery with and without fusion.

Introduction. Decompression is the gold standard surgical technique in patients with symptomatic spinal stenosis not responding to conservative management. We present an audit of outcomes in a population of patients undergoing this procedure over a four year period. Method. All patients undergoing lumbar decompression were assessed preoperatively and between 4 and 12 months postoperatively using the Oswestry Disabilty Index (ODI %), pain scale (0–10) and patient satisfaction. The patient's age, the number of levels decompressed and the incidence of complications were recorded. Results. Data is expressed as mean ±SD. Of 127 patients 112 were available for follow up. Mean age at surgery was 68.8±11.8 years. 55% of patients had a single level decompression, 36% 2 levels, 9% 3 levels. L4/5 was the most frequently decompressed level (51%) Improvement in ODI was 13.9±11.7(p<0.0001), improvement in pain scores 2.9±3.0 (p<0.0001). Improvement was the same regardless of number of levels decompressed (ANOVA p=0.84). There was no association between outcome and age. Dural tears occurred in 8.9% of patients, with post operative infection in 2.7%. The presence or absence of post operative complications did not significantly affect outcome. Based on outcome 87% of patients were happy with their surgical experience and outcome. Conclusion. Lumbar decompression remains an effective treatment for stenosis by improving ODI and pain scores. Age and number of decompression levels do not influence outcome. There is a high level of patient satisfaction with the procedure

Study Design. A prospective cohort study was carried out looking at the functional outcome and post-procedure translational segmental instability after multi-level lumbar decompression using a Hinge osteotomy technique. Objective. The Hinge osteotomy technique involves unilateral subperiosteal muscle dissection with osteotomy of the base of the spinous processes thereby preserving the integrity of the posterior elements. The objective of this study was to demonstrate the results of this technique clinically and radiologically. Methods. Between February 2005 and February 2007, 120 patients (51 male and 69 female) diagnosed with degenerative and/or congenital lumbar stenosis with a mean age of 64 years, underwent central and bilateral canal decompression using the hinge osteotomy technique. A mean of 2 segments (range 2-4) was decompressed. All patients were followed up for a minimum of three years. Five outcome measures were used: visual analogue scale for leg pain, Likert scale for functional status, symptom specific well-being score, general well-being score, and ODI score. The outcome measures were recorded pre-operatively and at 6 months and 3 years post-operatively. Successful surgical outcome was defined as an improvement in at least four out of five outcome measures. Results. 108 patients (90%) had a successful surgical outcome. There was a statistically significant improvement in all outcome criteria (p< 0.001) when measured at the 6-month post-operative mark as compared to pre-operatively, with further marginal significant improvement (p< 0.05) at 3 years post-surgery. There was no evidence of progressive lumbar segmental instability at 3 years post-operatively. Conclusion. Decompression of multi-level lumbar spine stenosis using the unilateral approach with the Hinge osteotomy technique is a safe approach for multi-level stenosis, with good outcome and no evidence of significant segmental translational spinal instability

We carried out a prospective study looking at the functional outcome and post-procedure segmental instability after lumbar decompression using a flip osteotomy technique that involved unilateral subperiosteal muscle dissection with hinging of the spinous processes thereby preserving the integrity of the posterior elements for unilateral or bilateral lumbar spine decompression. Between February 2007 and February 2008, 51 patients (29 male and 22 female) diagnosed with degenerative and congenital lumbar stenosis with an average age of 60, underwent central and lateral canal decompression using the flip osteotomy technique. An average of two segments (range 1-3 segments) was decompressed. Patients with a history of previous spinal surgery, spinal fusion, existing degenerative spondylolisthesis or cauda equina syndrome were excluded. All patients were followed up for a mean of 1.5 years. Five outcome measures were used – visual analogue scale for pain, Likert scale for functional status, symptom specific well-being score, general well-being score, number of days incapacitated in last 4 weeks. The outcomes measures were recorded pre-operatively, 6 weeks and one year post-operatively. Successful surgical outcome was defined as an improvement in at least four out of five outcome measures. 90% (46 patients) of patients had a successful surgical outcome. There was a statistically significant improvement in all outcome criteria (p<0.005) at the 6-week post-operative mark as compared to pre-operatively, with marginal improvement at one year post-surgery. There was no evidence of progressive lumbar segmental instability at one year post-operatively using our flip osteotomy technique. Decompression of the lumbar spine for lumbar stenosis using the flip osteotomy technique is a safe approach for one or multi-level stenosis with good outcomes and no evidence of significant iatrogenic segmental spinal instability. We declare no conflict of interest and ethical approval was obtained

To determine if the surface area of partial thickness (< 50%), Bursal side tears of the cuff influence outcome following Subacromial Decompression. Shoulder function using Constant score (CS) was recorded before and a minimum of one year after Arthroscopic Subacromial Decompression (ASD) in patients undergoing surgery for primary impingement. In patients who had partial thickness, Bursal side tears (BT), the length of the tear in its largest dimension (surface area) was measured. These patients were divided into two groups according to the tear surface area (≤9 mm and ≥10mm) .To determine whether having a BT (< 50% thickness) or its surface area affect pre and postoperative CS, t-tests were performed. 110 patients underwent ASD over a one-year period for primary impingement. 22 patients with partial thickness BT and18 patients with intact rotator cuff were included in this study. In 10 patients, the BTwas ≤9 mm (mean7mm) and in 12 patients BTwas ≥10mm(mean13mm). Statistical analysis of Pre-& postoperative Constant scores showed that, in ≤9 mm group CS increased significantly by 21.5, p=0.02, 95% CI (4.9, 38.1). CS increased in ≥10mm group by 22.8, p< 0.01, 95%(11.5, 34.1). Comparing the change in CS between these two groups with different tears size, there was no significant difference (2-sample t-test, t=0.15, 20df, p=0.88). To determine whether having BT tear affects pre- and post-operative Constant scores, all BTs were grouped together and compared with the group of patients with intact cuff. In the group with BTs, average Constant scores increased significantly (paired t-test,t=5.24,21df,p< 0.01) by 22.2 with 95% CI (13.4, 31.0). In the group with no tears, average Constant scores increased significantly (paired t-test,t=5.17,17df,p< 0.01) by 26.6, 95% CI (15.8, 37.5). Comparing the levels of absolute change in Constant scores from pre- to post-operation between the two groups there is no difference in outcome between patients with a tear and those without a tear (2-sample t-test, t=1.03, 38df, p=0.31). We conclude that ASD yields satisfactory results in patients with BTs involving < 50% thickness, irrespective of the surface area of the tear

Introduction and Aims: To determine if the surface area of partial thickness (< 50%), Bursal side tears of the cuff influence outcome following Subacromial Decompression. Method: Shoulder function using Constant score (CS) was recorded before and a minimum of one year after Arthroscopic Subacromial Decompression (ASD) in patients undergoing surgery for primary impingement. In patients who had partial thickness, Bursal side tears (BT), the length of the tear in its largest dimension (surface area) was measured. These patients were divided into two groups according to the tear surface area (≤9 mm and ≥10mm) .To determine whether having a BT (< 50% thickness) or its surface area affect pre- and post-operative CS, t-tests were performed. Results: 110 patients underwent ASD over a one-year period for primary impingement. Twenty-two patients with partial thickness BT and 18 patients with intact rotator cuff were included in this study. In 10 patients, the BT was ≤9 mm (mean 7 mm) and in 12 patients BT was ≥10mm (mean 13 mm). Statistical analysis of pre- and post-operative Constant scores showed that, in ≤9 mm group CS increased significantly by 21.5, p=0.02, 95% CI (4.9, 38.1). CS increased in ≥10mm group by 22.8, p< 0.01, 95%(11.5, 34.1). Comparing the change in CS between these two groups with different tears size, there was no significant difference (2-sample t-test, t=0.15, 20df, p=0.88). To determine whether having BT tear affects pre- and post-operative Constant scores, all BTs were grouped together and compared with the group of patients with intact cuff. In the group with BTs, average Constant scores increased significantly (paired t-test, t=5.24, 21df, p< 0.01) by 22.2 with 95% CI (13.4, 31.0). In the group with no tears, average Constant scores increased significantly (paired t-test, t=5.17, 17df, p< 0.01) by 26.6, 95% CI (15.8, 37.5). Comparing the levels of absolute change in Constant scores from pre- to post-operation between the two groups there is no difference in outcome between patients with a tear and those without a tear (2-sample t-test, t=1.03, 38df, p=0.31). Conclusion: We conclude that ASD yields satisfactory results in patients with BTs involving < 50% thickness, irrespective of the surface area of the tear

The use of interspinous distraction devices should remain the subject of audit and research. They are a relatively new addition to the armamentarium of surgical treatment of lumbar spinal stenosis. The reported results are variable and there are a number of different devices available. It is recognised that there is an early failure rate with interspinous distraction devices. This is a report of the clinical results after conversion to segmental lumbar decompression following a failure of interspinous distraction procedure.

18 patients had removal of device and conversion to a standard lumbar decompression at an average of 13 months after the index procedure. There were 7 females and 11 males. The average age was 68 years (range 49-85). The two youngest patients had a decompression and instrumented fusion, the others had decompression alone. Prior to the Index procedure of stand alone interspinous distraction device the average Oswestry Disability Index (ODI) was 42 and Visual Analogue Score (VAS) leg 7.2. Prior to revision the average ODI was 42 and VAS leg 6.7.

Complications: One intra operative myocardial infarction, one incidental durotomy and one post operative infection (pseudomonas isolated).

At a mean of 9 months follow up the average ODI was 23 and VAS leg 2.1. The VAS back was 1.9. The walking distance was subjectively reported as 246 yards pre op and 1100 yards post procedure. There was a clinically significant improvement in all patients.

A failed interspinous distraction device can be satisfactorily salvaged with a segmental lumbar decompression.

The Patient Evaluation Measure (PEM) was designed at the Derby consensus meeting in 1995. It was validated for Carpal Tunnel Syndrome (CTS) in 2005 (Hobby et al) and was preferable to the DASH score for CTS assessment. We aimed to audit CTS treated by surgical decompression in our unit using the PEM, and to compare our results with the published literature. Thirty consecutive patients undergoing carpal tunnel decompression were questioned about one hand. Patients completed a preoperative PEM and a postoperative PEM at 3 months. Mean PEM scores improved from 41.3 to 23.9 (P< 0.001). Individual questions showed statistically significant improvements in mean scores: Feeling in the hand, Cold intolerance, Pain, Dexterity, Movement and Hand in general (all P< 0.001): Work (P< 0.005): ADL (P< 0.01): Movements, Grip and Appearance (P< 0.05). Our results are similar to previously published series, both overall, and for individual questions in the PEM. Results for Carpal Tunnel Decompression in our unit match those of other units. We found the PEM was easy to use; and effective, both in the assessment of patients with CTS, and for outcome measurement following surgical decompression. Our study supports the idea that the PEM could be used widely as an audit tool, to assist Hand Surgeon and/or Hand Surgery Unit Appraisal

To assess the incision used for routine primary Carpal Tunnel Decompression (CTD), preferred modes of division of the flexor retinaculum and the accuracy with which the motor branch of the median nerve could be identified. A simple questionnaire was distributed at an orthopaedic regional meeting, which contained a list of simple questions, and a scale photocopy of the palm of a left hand. The surgeons were asked to indicate upon the hand the incision they would make and their prediction of the location of the motor branch of the Median nerve. The data was feed into a desk top spreadsheet program where it was analysed. 43 complete questionnaires were returned, comprising all grades from SHO to consultants. A great majority used a McDonald’s spatula during their division of the retinaculum, with an equal proportion cutting down onto the McDonald’s spatula as were cutting up from it. The shape of the incision was straight in a majority of cases, though some consultants and SpRs tended towards curved or S-shaped incisions. Length of incision varied, among all grades, from 2cm to 6cm, with Juniors tending towards shorter incisions. With respect to Ulna (Medial) or Radial (Lateral) position of the incision, the tendency was to place the incision Radially. 72% of surgeons located the position of the motor branch within 2cm of the actual position, as predicted by Kaplan’s lines. The surgeons audited tended towards lateral incisions, and hence potentially placing the palmar cutaneous and the motor branches of the median nerve at greater risk. Some juniors continue to have the preconception that smaller incisions for CTD are preferred. The location of the motor branch was accurately predicted in a majority of cases. The McDonald’s spatula is still widely used in CTD

Aims

The aim of this study was to determine whether early surgical treatment results in better neurological recovery 12 months after injury than late surgical treatment in patients with acute traumatic spinal cord injury (tSCI).

Sub-Acromial Decompression (SAD) for impingement has a failure rate of 5–20%. We used MRI to see whether SAD failure is associated with muscle wasting or fatty degeneration in the rotator cuff. Fifty one patients with impingement were assessed using MRI pre- and post-op. Following arthroscopic SAD, seven patients with cuff tears were excluded. This study reviews the pre-op and 6 month post-op MRIs of the remaining 44 patients (25 males; 19 females) and also 17 additional MRIs obtained at three years post-op. MRI assessment was performed by an experienced radiologist using Zanetti’s muscle bulk assessment with values expressed as standard deviations from an age matched mean and Goutallier’s fatty degeneration assessment graded 0 to 4. There was a wide range of pre-op muscle bulk values (SupraSpinatus minus;2.4 to +3.4; SubScapularis minus;2.1 to +4.8; and InfraSpinatus/ Teres Minor minus;1.1 to +5.7). Comparing post-op with pre-op there was a gradual trend towards a reduced muscle bulk for each muscle after surgery but to a limited extent only (< 0.5SD). Pre-op fatty degeneration of SS and IS was grade 2 in about a half with a mild increase with time post-op (SS pre=50%, 6/12 and 3 years=59%; IS pre=45%, 6/12=43% and 3 years=59%). There was a similar age distribution for grades 1 and 2. Only three of the patients were a clinical failure at 6 months but this increased to five of the 17 patients scanned at 3 years. Predicting these failures was not possible based on the pre-op MRI data. The high initial success of SAD was not accompanied by an overall increase in muscle bulk or quality of the muscle at 6 months. The progressive loss of muscle bulk and quality over 3 years was accompanied by an increased clinical failure rate

Tibialis posterior tendon (TPT) dysfunction is a disorder of unknown aetiology. Trauma, inflammatory processes, anatomical abnormalities and iatrogenic factors have all been implicated as causative mechanisms. The condition presents with pain and swelling around the medial malleolus. The pain is characteristically worse on exercise and relieved by elevation. The disorder has been classified by Johnson and Strom (1989); stage I is characterized by pain around the medial malleolus and mild weakness of single heel raising. Without treatment the condition may progress to a fixed valgus deformity along with pes planus. Aim. To assess the outcome of surgical decompression of stage I TPT dysfunction. Method. Ten cases were identified, operated on by a single surgeon over a three-year period. The patients were assessed in a dedicated clinic by administration of a questionnaire and by clinical examination. Results. Nine patients with an average age of 30 years (13–51) agreed to participate in the study. Six of the nine patients recalled a sporting injury to the ankle prior to onset of symptoms. Eight of these of patients underwent a course of physiotherapy prior to surgery. After decompression all patients reported reduction of pain as measured using a visual analogue scale, with five patients reporting complete resolution of pain. Patients experienced relief of pain on average four weeks (1.5–6) after surgery. All patients were able to return to work and normal leisure activities after appropriate rehabilitation. Conclusions. Decompression of the tibialis posterior tendon in stage I dysfunction leads to pain relief and enables an early return to normal activities. Therefore surgical decompression of the tibialis posterior tendon may be considered in cases of stage I dysfunction which are refractory to conservative measures, particularly in young and active patients