Spinal surgery in obese and morbidly obese patients can be challenging to the operating surgeon. One of the major problems is obtaining a good surgical access. We have used the synframe retractor system in patients undergoing spinal fusion and have found it especially useful in obese and morbidly obese patients. This study reports our experience.

Seventy-seven consecutive obese and morbidly obese patients that underwent spinal decompression and fusion were reviewed. Patient selection was based on BMI values. Those with a BMI of more than thirty were included in the study. There were thirty-eight females and twenty-five males with an age of twenty-one to eighty-one years. Patient charts were used to acquire information regarding age,weight,height,gender,time in surgery, procedure start and end time,and departure. Postoperative complications and length of hospital stay were also recorded. Anesthesia notes were used to determine ASA scores,number of preoperative morbidities,and intraoperative blood loss. The synframe was used on all the patients. It is a retractor system which consists of a ring placed around the surgical site. It is fixed to both sides of the operating table with arms. Using retractor blades, the ring allows 360 degree access to the surgical exposure from any side.

The set up tme for obese patients was 59.8 minutes and 73.5 minutes for morbidly obese patients. The surgical time and blood loss was only marginally higher in these two groups than in normal weighted patients. The average postoperative length of hospitalisation was 5.8 days. The surgical incision length averaged 7.8 cms for single level and 11.5 for two level fusions. 44% patients suffered a complication. These included cage migration due to a fall, wound infection, dural leak,pulmonary embolism, deep vein thrombosis etc. No significant weight loss was recorded following the surgery.

Obese patients are a surgical challenge due to the comorbidities and difficulty in positioning and gaining good surgical access. The use of synframe retractor system improves surgical access, thereby reducing surgical time and blood loss. The surgical incision length was also comparable to normal weighted patients using this system. No significant weight loss was recorded following surgery. The high complication rate can be attributed to the associated comorbidities.

This study was performed to evaluate the clinical and radiographic outcomes in patients undergoing anterior cervical discectomy and fusion (ACDF) with rhBMP-2 and polyetheretherketone (PEEK) cages with our standard treatment of allograft spacers and demineralised bone matrix.

Forty-six patients who underwent primary ACDF were included in the study. Twenty two patients with PEEK spacers and rhBMP-2 were compared to twenty four patients with allograft spacers and demineralised bone matrix all supplemented with an anterior locking plate. All patients were examined preoperatively and at two, six, twelve and twenty-four weeks and one and two years following surgery. Their cervical Oswestry scores,VAS for neck and arm pain and a pain diagram were recorded at every visit. A radiographic examination was also performed and patients were questioned for dysphagia, hoarseness of voice and any other difficulties. Radiographs were evaluated for prevertebral swelling, bone formation, subsidence and likelihood of fusion. CT scans were performed in any individual at twelve months if there was a concern of non union.

There was no significant difference in pain scores between rhBMP-2 and allograft spacer patients. There was improvement in both groups from their preoperative scores. Incidence of hoarseness of voice was also similar in both groups. There were statistically significant more patients with dysphagia in the rhBMP-2 group at two and six weeks following surgery. All patients in the rhBMP-2 group achieved a radiological diagnosis of probable fusion at their latest follow up (thirty-eight levels). In the allograft group 23/24 patients achieved a diagnosis of probable fusion (39/40 levels). End plate resorption was observed radiologically in 100% of the levels where rhBMP-2 was used. Prevertebral swelling on lateral radiographs was significantly greater in patients with rhBMP-2 causing dysphagia. The cost of implants was three times higher in patients with PEEK cage and rhBMP-2.

The use of rhBMP-2 leads to consistent fusion in the cervical spine. Significantly higher rates of prevertebral swelling, dysphagia and s higher cost are major drawbacks. End plate resorption was an unusual radiographic finding with the use of rhBMP-2.

RhBMP2 was used in thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF) using anterior cervical locking plates and lumbar posterior pedicle screw constructs. All patients showed radiographic fusion at six months. Early lucency, subsidence, and increased pain occurred between six weeks and three months in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% in ALIFS, 24% in TLIFS, and 53% in ACDF. Pain improved by the sixth month. We recommend alternative structural support when using RhBMP2.

To determine effectiveness of RhBMP2 in interbody fusion with machined allograft spacers (MTF Synthes Spine USA femoral ring, TLIF and fibular ring cervical spacers)

A prospective study of thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF). Machined allograft spacers and RhBmp2 were supplemented with anterior locking plates in the cervical spine while the lumbar segments were supplemented posterior pedicle screws constructs. Patients were followed at two weeks, six weeks, three months, six months, one year. Patients were examined, had xrays, completed Oswestry scores, pain diagrams, and VAS for pain preoperatively and at every follow up appointment.

All the patients showed radiographic evidence of fusion at six months after surgery. Early lucency and subsidence of allografts was observed in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% (range13–42%) in ALIFS, 24% in TLIFS (range 13–40%), and 53% in ACDF. Subsidence and reporting of increased pain occurred between the six- week and three month follow up after which patients improved.

Although high rates of early fusion can be accomplished with allograft spacers and rhBMP2 significant subsidence occurs in greater than 50% of lumbar cases and 30% of cervical cases due to early turnover and loss of structural support of the allograft. We recommend alternative structural support when using RhBMP2.

Dislocation after hemiarthroplasty for femoral neck fracture is a rare event. Two hundred nineteen patients underwent hemiarthroplasty for femoral neck fracture all with a modern stem and modular unipolar prosthesis at our institution over a three year period. Eleven patients (4.1%) suffered a dislocation. Epidemiologic, technical and anatomic-radiographic factors were reviewed to assess risk factors for dislocation. Our findings indicate that. Mental disease was a significant risk factor. Femoral neck offset and center edge angle of the acetabulum were also contributing factors for dislocation.

To determine the risk factors for dislocation after hemiarthroplasty with a modern stem and modular unipolar prosthesis for femoral neck fracture.

A retrospective review was undertaken at our institution from January 2000 to December 2003. We reviewed factors including gender, age, time of dislocation, medical comorbidities, side of operation, surgical approaches and radiographical data including femoral neck offset, contra lateral femoral neck offset, center edge angle, residual femoral neck, prosthesis femoral neck shaft angle and acetabular index.

Hemiarthroplasty for femoral neck fracture was pre-formed on two hundred and nineteen patients all with a modular unipolar prosthesis. Eleven patients (4.1%) had at least one dislocation during a one year follow-up. The average time of dislocation following surgery was 19.3 days (std 12.7days). There were no significant difference for gender, age, surgical approach, residual femoral neck, and prosthesis femoral neck shaft angle. There was a statistical significance of mental disease in 55% of dislocated hemiarthroplasty compared to 21% of nondislocated hemiarthroplasty but other comorbidities were not a factor. Median femoral neck offset of nondislocated hemiarthroplasty measured 51mm versus dislocated hemiarthroplasty value of 47mm, a difference of 4 mm (P=0.043). Center edge angle of nondisplaced hemiarthroplasty measured median thirty-six degrees versus a median of thirty-two degrees for dislocated hemiarthroplasty, a difference of four degrees (P=0.006).

The factors predicting dislocation are likely multifactorial. Our findings indicate that Mental disease was a significant risk factor. Femoral neck offset and center edge angle of the acetabulum are contributing factors for dislocation.